On Saturday Trump fired the first salvo in what's expected to be a world-wide trade war, with 25% tariffs on goods from Canada and Mexico, and an additional 10% on goods from China. Tariffs on specific Chinese imports have largely been in effect since his 1st term, 2017-2020, with some being increased under Biden. Before leaving office Biden also implemented restrictions on which processors could be exported to China, and proposed adding more processors to the list. No one knows yet if this will continue, or possibly expand. It's been announced that the EU is a future target for tariffs, possibly in mid-February, especially Denmark, as Trump tries to gain control of Greenland. Targeted countries will respond with tariffs and import/export restrictions of their own -- Canada has already released it's initial list of tariffs on US imports, which will expand later in February if the situation continues. China has already set up export controls on rare earth metals etc. [used for batteries and tech], which is a market they largely control, and is expected to expand export controls to other materials. It's been announced that US tariffs on electronic chips, including a proposed 100% tariff on chips from TSMC, the world's leading fab in Taiwan, are coming shortly. It's unknown so far if these tariffs would effect products assembled elsewhere using chips from TSMC, e.g., Apple phones.
Needless to say, prices of PCs, laptops, and the components they use *might* soon skyrocket in the US. And if or as sales in the US decline, an oversupply *could* mean lower prices elsewhere, though the effects of the trade war on electronics are unpredictable. TSMC for example could lose a lot of orders, and be forced to raise prices to meet the costs of staying in biz.
At any rate, the one sure thing is that we've got just weeks left of status quo pricing for PCs, laptops, and related goods, and whatever happens after that may last for 4 years, or more. IMHO that makes now a good time to evaluate your needs over the coming years. It's a gamble. Depending on where you live prices could rise or drop, maybe drastically. To try and be helpful I've written about what to look for in a new or used laptop or PC, the parts you'd use to upgrade an existing PC, and the parts to build one. When it comes to upgrades & what to replace, it's impossible to predict how long any component will last, but very generally about 6 years is I think a fair guesstimate. You can plan on components lasting 6 years, and while they may in fact last 10 or 12, that's not something you can plan on. Then in a part two, I've written about how you go about the physical process of upgrading a PC.
Building a PC, or upgrading one you already own isn't hard -- most stuff is standardized, so 99% of the work is mounting components and plugging things in. If you're building a PC, you have complete choice and/or control regarding the parts used, & upgrading one or more components in the future is usually easier, though the cost of a complete PC can be higher. While you can argue that some components will be higher quality, and so should last longer, that's not really a safest bet. [There's a huge amount of pretty old Dell, HP, & Lenovo PCs out there.] Your upgrade options are more limited with mini-PCs and laptops since neither are designed to be serviced. With either of those start by tracking down service manuals online, determining what can be replaced with parts you can easily buy, if replacing them requires any special tools or skills, and most importantly, if it's something that you feel you can handle. Note that with laptops, particularly less expensive models, you can expect stuff like some of the retaining clips that are part of a plastic casing will break off, threaded inserts will come loose etc. With a tablet you're probably limited to replacing the battery or display, and disassembly is difficult, especially when things are held together with glue that you have to heat to soften/melt.
* * *
The CPU determines performance.
Before spending any money, the starting point is deciding the level of performance you want/need from a PC or laptop. That means deciding on the specific CPUs that you will consider. Otherwise you risk buying something that just cannot meet your needs, or on the flip side, paying extra for performance you'll never use. At the very low end, e.g., an Intel Atom [N series] CPU or equivalent, you get both the lowest price and the very minimum performance necessary to run an OS like Windows. Linux will generally perform a little better with these CPUs, while in Windows some tasks like the monthly updates can actually be painful. You can play games like Candy Crush from the Store, &/or the games offered on GOTD. They're also good for watching / playing video, even 4k, and if you're patient -- opening a browser can take a little while -- they're OK for web browsing. The top end is of course the most expensive, where you run the risk of paying for more performance than you'll ever use. Most people are happiest with something in the middle, where Windows starts very quickly and your installed apps seem to start instantly. If you're doing something more intensive -- heavy photo or video editing, complicated spreadsheets, VMs etc. -- you might be happier leaning towards the upper mid range.
If you want to use your PC / laptop for gaming, you should also consider the GPU [Graphics Processor]. Many CPUs come with a GPU built in, and if that GPU meets your needs, you'll save money. A few CPU models have above average graphics performance for gaming. e.g., AMD's 5000 or 8000 G series, or a few of Intel's newest, but there are often tradeoffs, like a slightly less powerful CPU. New CPUs are coming in 2025 that have significantly better GPU performance, but details including future availability, pricing etc. are uncertain. A minimal graphics card, e.g., the AMD RX 6600, sells for ~$200 in the US -- new lines are coming out from AMD, Intel, & Nvidia, so that's subject to change. Intel has a new graphics card out with an MSRP of $220, but they're hard to find, especially at that price. If you opt for a separate graphics card you might be able to save a few dollars by buying CPU without a GPU built-in, but you have a more limited choice, and you might not find one with sale pricing. Pretty much any graphics card will outperform a built-in GPU, you'll need one for things like AI-based photo/video editing, and you'll need one for more advanced games, especially at higher resolutions. Laptops with a separate GPU are not as common, and cost more. The different models of graphics cards, or separate GPUs in a laptop, are basically a matter of how much performance you can afford. Many people buy used graphics cards from gamers who always want, and can afford the latest models.
Doing the research, comparing CPU prices and performance can be time consuming but necessary. CPUs for desktop PCs aren't too bad... Intel has the i3 chips [& their equivalent using Intel's new naming], which are the lowest you can go and still have performance you can live with for light games, web browsing, word processing etc. The Intel i5 is pretty much smack in the middle, and is the most popular -- the AMD CPUs competing with it are the 5600, 7600, & 9600, with or without an added x. The higher the number the newer the chip. The i7 is Intel's upper mid range CPU, and the AMD equivalents are the 5700, 7700, & 9700. again with/without x. The 5000 series use older motherboard designs with the AM4 CPU socket, meaning you might save a few dollars on the motherboard & RAM. You can find comparisons and benchmarks online comparing the performance of each of these CPUs, along with details on AMD's gaming-focused, & more expensive X3D series. Bear in mind that you want to find comparisons and/or benchmarks that apply as closely as possible to how you plan to use the PC or laptop, e.g., gaming benchmarks won't reflect performance working with spreadsheets or Photoshop. Try not to get distracted by a CPU's core count -- more cores &/or threads look good on paper, but don't always translate to better performance with your chosen tasks, e.g., Adobe's Photoshop docs say more cores can be a waste of money.
Comparing CPUs in laptops, tablets, and mini-PCs OTOH is confusing because there's such a Large variety available. A laptop CPU can use older hardware designs, new designs, or some combination of both. Performance & power draw / battery life can vary a Lot. Look for the specific model number of the CPU, not just it's more general family name, so you can find accurate comparisons.
There are also the new ARM CPUs in laptops [they're coming to PCs]. They have great battery life, which new AMD & Intel CPUs can come close to matching, but software compatibility is a problem, and gaming performance generally sucks. These laptops earn their Copilot+ designation by including an NPU [Neural Processing Unit] to help with AI, plus it takes some of the load off the more power hungry GPU to give better battery life. AMD & Intel have their own versions. Microsoft does have a few features in the latest version of Win11 that are only available on qualifying laptops with an NPU, but whether those few features are meaningful or not is up to you. Note that some future use cases might benefit from AI running locally on a laptop or PC's NPU, but for now AI software that's not part of Windows favors using a graphics card instead, regardless Microsoft's marketing.
Memory / RAM
When you look at PCs or laptops at any retailer, one of the 1st things they'll tell you is the CPU, followed by the amount of RAM. Programming code for software along with your data are stored in files on the hard disk / SSD. When you run software the necessary programming code, along with whatever data is read into memory, where the actual program execution happens. If / when the memory storage fills up, Windows sort of extends the available memory by offloading some of the stuff currently in RAM to the hard disk / SSD. Windows 10 is very good at that -- Win11 is even better.
And that goes directly to how much RAM you should *ideally* have installed in your PC or laptop. If you can keep everything in RAM, without Windows using the hard disk or SSD for overflow, you'll get better performance, because RAM is faster than the fastest SSD. Win11 will run with only 2GB of RAM [like my old tablet], while the current trend for gaming seems to be 32GB [though 64GB is gaining ground on Steam], and mainstream PCs / laptops often have 16GB. You can get an idea of how RAM hungry your software &/or games are by watching the memory use in Task Mgr. Things like VMs [Virtual Machines], large, complicated spreadsheets, large photo & video editing etc. all tend to use more RAM when it's available. If you're interested in gaming using the built-in GPU, more & faster memory is often a good thing, since that built-in GPU doesn't have any RAM of its own, but that varies depending on the CPU. That said, you can have more RAM than necessary, more or less wasting some of the money you spent. If you want / need to save money, cutting back on RAM is one of the safer ways you can do that without compromising performance too much. And with a desktop PC, some mini-PCs, and a relative few laptops, you can upgrade the RAM later on when you have the money. Note: RAM is commonly sold in pairs of 2 sticks [though there are sets of 4], and you should Never mix & match.
You'll generally find 2 main types of RAM currently, DDR4 & DDR5. DDR5 is faster & may be more expensive. What type of RAM is used is determined by the motherboard -- older designs use DDR4, while newer designs specify DDR5. RAM is rated at different speeds, with a base clock, usually a mild overclocking preset, and often an unofficial overclock that enthusiasts *usually* can achieve. How much performance is helped by increased RAM speeds depends on the CPU, but most CPUs seem to have a sweet spot where they do best [you'll usually find recommendations along with benchmarks and reviews]. The manufacturer's reputation and motherboard compatibility for the specific brand & model of RAM you're considering is critical -- diagnosing memory issues is a truly miserable experience. Try to check the motherboard manufacturer's qualified memory list for that model before you buy -- you won't always find what you're looking for, but if the RAM is listed it's a safer bet.
Hard Disks & SSDs
How much storage you should have or will need is really an individual thing. Windows 11 itself requires about 30GB if you're good about removing garbage and temporary files. Everything else adds to that -- software, games, photos, videos, music etc. Of course, not everything has to be stored on an internal drive -- an SSD in an external housing connected via USB, especially USB 3 gen 2, can give you performance surprisingly close to what you'll get using an internal drive. Conventional hard disks work as external USB drives too, and may allow you to save money when performance isn't critical.
Conventional hard disks with spinning platters are still a thing. Performance and longevity vary. Drives spinning at 7200 rpm are faster than cheaper drives spinning at 5400 rpm. Conventional hard disks are generally much cheaper than SSDs at capacities of 1TB or more. Once Windows gets going -- all processes and background apps running -- you *may* not notice that much of a difference compared to Windows on an SSD. Having Windows on a smaller, cheaper SSD that will start up much faster while having all your data & games etc. on a conventional hard disk is Very viable -- again you may not notice much if any difference compared to using all SSDs. Conventional drives generally need active cooling. Two issues you might encounter are modern PC cases may not have anywhere to mount conventional hard disk drives, &/or it may be difficult to mount them where they will be cooled. Specs vary, but exceeding the max safe drive temperature can cause a hard disk to malfunction including loss of data.
SSDs come in two form factors, vary greatly in speed, longevity, and price, and may need active cooling. They also generally perform best when at most 1/2 full, rather than at or near their full capacity. 2.5 inch SSDs use the same form factor as the 2.5 inch hard disks often used for laptops and external drives. The fastest drives generally top out at the same speeds as the SATA connections themselves. They normally do not require cooling, and can be mounted just about anywhere in a PC case. M2 drives may be SATA, but are usually NVMe, which is newer, faster tech. They come in different lengths, and are narrow, thin circuit boards that fit into special sockets on the motherboard. NVMe drives connect over the PCIe bus, and may be 3x, 4x or 5x rated. Faster drives may need heat sinks, and the fastest drives may need a heat sink with a fan. Like CPUs, when they approach their maximum temperature they will start to self throttle, reducing speed until temperatures drop. Having Windows boot partition on an NVMe drive *may* be challenging to get working. Because there are a limited number of PCIe lanes available, installing an NVMe drive in an empty socket may reduce bandwidth elsewhere, e.g., one of the card slots. That varies by motherboard make & model so check the specs & docs.
The capability to replace or add hard disks / SSDs to a PC, laptop, &/or a few tablets varies. Some are designed to make replacing the drive quick & easy, and many people buy devices designed that way intending to immediately replace the drive that came with it, because they can buy one with more capacity cheaper than the add-on cost.
Additional parts for building/upgrading a PC
The Motherboard or Main Board
Once you've chosen a CPU, if you're building a PC, or upgrading but the new CPU will not work in the current motherboard, you need to select the motherboard that everything else connects to. AMD and Intel release a new motherboard design & chipsets with every new generation of CPUs, generally at a few performance / price levels. CPUs fit into a socket on the motherboard, and that particular socket may be used on only one generation of CPUs and motherboards, or it may be used for several -- AMD promises to use their AM4 & AM5 sockets for 7 years. Currently AMD uses the AM5 socket on 600 & 800 series motherboards, and their latest CPUs work with either. Depending on the CPU, you might be able to do the same with Intel. Each new generations of motherboards typically adds features, e.g., the AMD 800 series adds USB 4.
There are several well-known companies that make motherboards, e.g., Asus, Gigabyte, MSI, Asrock etc., each building on the reference AMD & Intel designs with several models, each having different features. These boards generally come in 2 sizes, the full size ATX, and a shorter, cheaper mATX designed for smaller cases. Most of the features are easy enough to decide on, like the number & speed rating of M2 sockets or USB ports, or maybe the audio chipset used. Buyer reviews can sometimes tip you off to issues -- you might be cautious about buying a board with several DOA [Dead On Arrival] complaints -- while pro reviews seem to focus on the VRM circuitry supplying power to everything on the board. The VRM & its cooling are important, those reviews tend to leave an awful lot unsaid. Pro review web sites & videos also tend to cover the motherboards that are sent to them by manufacturers, which are often their pricier models.
If the CPU you want to use is newer than the motherboard you'll usually have to update the BIOS firmware for the new CPU to work. There's a catch -- updating the firmware can require a CPU installed that does work. If you're replacing both the board & CPU then you want to look for a feature where you can update the BIOS without having any CPU installed.
The Power Supply
You need power for the PC to work, and that's where the power supply comes in. Many brand names sell both good & bad models at different wattages. UL &/or CE markings are optional, and may not in fact mean that the power supply passed any sort of checks whatsoever. Power supplies have been sold that actually contained rocks instead of electronics. You can find detailed reviews for a few power supplies where pros actually take it apart, check the quality of the components, and then measure the actual voltage output, giving you confidence that it's a reasonable buy. When you consider that the power supply is THE Part that you plug into the wall socket, you do want to be careful selecting one.
Power supplies have different efficiency ratings, e.g., bronze, silver, gold etc., meant to reflect how much of the electricity from the line cord is actually being supplied to your PC, and how much is wasted. They're rated and sold by their maximum output in watts, performing most efficiently when supplying roughly 1/2 their max, e.g., if you need 300 watts use a 600 watt power supply. You'll find more than a dozen power supply calculators online, where you enter the CPU, GPU, drives etc. and it will give you a wattage recommendation. Power supplies can be fully or partially modular, or not -- modular means that the individual cables that you need & use are plugged into the power supply, so you don't have to worry about what to do with those cables you don't use. IMHO the practical advantage is that extra cables, and any extra cable length for the cables you do use, can block airflow, and that contributes to more heat inside the case. Many people OTOH probably just feel that it just looks neater not having extra cables bundled up.
The PC Case
At the most basic level you need a frame to attach the motherboard to, and they do sell open cases that are little more than that. Put everything in an enclosure [case] and the main issue is cooling -- everything in that case produces heat, which in turn is bad for everything inside that case. Practically speaking, the difference between a good case & a bad case is airflow, because the more directed airflow there is, the cooler the temps inside that case will be. Look for pro reviews where someone actually puts a PC together using the case under review, and measures the temperatures of the PC's components with it running under load. As with power supplies and motherboards, the cases that receive pro reviews tend to be pricier -- you might get away with buying a cheaper case that looks very much like one that got a pro reviewer's blessing, with the same basic fan locations etc.
Another consideration in the sturdiness & build quality, which will matter to some people more than others. A sturdier case can be moved more often, and can be opened more often, e.g., for upgrades or cleaning, without warping, but even a less expensive case using thinner sheet metal can last over a decade. Some cases are much easier to remove the side panels than others, and may have features that make it easier to install drives &/or add-on cards. A larger case gives you more room for your hands to plug things in, but it takes up more room. Some cases have more room on the backside, behind where the motherboard mounts, for routing cables -- some people like the added neatness, and it can improve airflow. I like having filters over the fans & AIO cooler radiator to stop dust, and some cases come with filters. I've also bought material used as pre-filters on small home air purifiers, and attached that to the case using Velcro or magnets. If you use filters remember that you have to periodically clean them, but they do cut down on dust clogging the fins of a CPU air cooler or the radiator for liquid cooling. If you opt to use a liquid cooler for the CPU, be aware that the radiator thickness and hose length of AIO or self contained units varies. Depending on the inside dimensions of the case, some radiators can't be mounted at the top of the case since they're too thick to clear the motherboard, while other AIO coolers have hoses that are too short to mount the radiator anywhere but up top. If you're going to use an air cooler for the CPU, note the cooler's height, because the case needs to be wide enough that you can put the side panel back on.
Some brands have a very good reputation for cases, are more likely to sell spare parts for their cases, have good to great customer service, are more likely to provide instructions with details on how everything comes apart, and because of all that can be a safer bet. However, while all of that's nice to have, that doesn't mean that a cheap case from a no-name brand can't work just as well for you, especially if you rarely open the case, e.g., my wife doesn't use her PC that much, so I can go a year without having to clean it out inside. Eventually the side panels may not go back on as easily, and you might get some paint chips where those panels attach, but the only things that can wear out really are the switches and any ports on the front of the case. You can buy generic replacement switches cheap, though it can be a real job to replace them, and you can also buy replacement switches that sit on your desktop. The ports at the front of the case are another matter. I've never had an old style USB port go bad over the years, and it's no big deal to plug a USB hub into the back of the PC. Many motherboards however do not have a higher speed USB C port on that back panel, but just one internal socket for a USB C cable from the front of the case. The USB C port on the front of this case didn't last 2 years., but luckily Corsair sells a replacement switch panel. Immediately after installing the new panel I stuck a 4 port USB C hub on the front top edge of the case with sticky tape, figuring I'd plug that in once, and never have to plug/unplug anything into that port again. Within a year one of the USB C ports on that hub wore out / went bad. Needless to say I'm USB C skeptic.
It can be important to make sure that the seller has a good return policy. There are some things that you just can't tell until you have the case in your hands and start to take it apart. I bought a case with a good brand name [Corsair] from Amazon, and promptly returned it. The front panel was designed to snap on/off, and since it had a filter behind that front panel, it would have to removed for cleaning at least once every 2 months. Problem was, pulling that panel off that often, I didn't think the parts would last a year -- it was just too flimsy a design. PC cases are also big, bulky things to ship, and so are more likely to get banged and thrown around by shipping company employees. I had 3 cases shipped by Amazon, and every one was damaged -- one was actually accordioned in the middle. I wound up keeping the least damaged one and Corsair itself sent me a new side panel for free.
Fans and CPU coolers
You need a CPU cooler -- how big or capable it needs to be depends on the CPU and if you intend to overclock it. Online reviews will tell you how hot the CPU gets, and often give you an idea of the cooling you'll need to run it. You can also find air & liquid cooler reviews, with charts showing how effective a given make and model is. Air coolers use a fan or fans to blow air across their cooling fins. Those fans are the only moving parts and can often be easily replaced. Air coolers work best with good airflow and lower temperatures inside the case. Liquid coolers use a pump mounted over the CPU to circulate coolant through a radiator that has 1-3 fans blowing through it. Those fans can be mounted to blow hot air from inside the case through the radiator, or to suck in cooler air from outside the case. Both types of CPU coolers mount in contact with the CPU for heat transfer, and a special dielectric paste or putty is used between the 2 surfaces. A new cooler will usually come with putty pre-applied, but there are dozens of thermal pastes you can buy, and you can also find comparative reviews online.
Case fans are broadly divided into 2 categories, those with PWM & those without. A current motherboard will vary the fan speed according to the temperature measured using sensors built into the motherboard at different locations -- usually you can select which sensor is used to regulate which fan(s), typically the CPU, VRM, motherboard chipset etc. It can do this better if the fan has PWM [Pulse Width Modulation]. PWM fans have 4-wire connectors and are usually more expensive -- those without have 3 -- though either should work with current motherboards. The number of fans that you can plug in on a motherboard varies by motherboard brand & model. You can buy fan controllers, which also come with some cases -- some will let you dial in speeds, or allow several fans to share one fan plug on the motherboard, and you can buy Y cables to plug two fans into one socket. Fan prices vary based on PWM or not, the size of the fan, the type of bearing used, the fan speed, the amount of air moved, and if it has RGB lighting. Some fan designs are quieter than others. When adding fans to a case you want a directed airflow, so air for example enters the front of the case, moves across the motherboard, its VRM heatsinks, and the graphics card if present, and then exits the rear &/or top of the case. You don't want air from opposing fans meeting in the middle of the case and just stagnating.
---------
How-To -- building or upgrading a PC
If you're upgrading the RAM, power supply, adding or replacing a video card, &/or adding or replacing case fans or drives, you only have to remove one or both side panels for access, depending on the case design -- the only exception is you might have to remove the front panel to replace one or more fans at the front of the case. There is no common design when it comes to those front panels, and unfortunately, there's often no documentation or instructions either. Most often both side panels of a case are easily removable to service everything inside. These panels are usually held in place by 2 screws each at the rear of the case. Some side panels have a row of catches on both the top & bottom edge -- once you remove the screws holding it in place, slide the panel a short way towards the rear of the case and it'll come free. Another popular design is to have the leading edge of the panel fit the front of the case in a way that acts as a hinge -- once the attaching screws are removed, the rear of the panel can swing out, away from the case, and then be pulled away from the front of the case. If there's a fan on one panel the connector at the end of the fan's wires should easily unplug from the motherboard -- there's no catch or anything. Fans are almost universally held in place by 4 somewhat thicker screws. Replacing or adding one is straightforward. The connectors can only be plugged in one way, and the motherboard's manual should show you where all the fan plugs on that board are located, &/or they're usually labeled on the motherboard.
To replace the RAM there's a release lever at one or both ends of each RAM slot that will eject the RAM when depressed. Leave the lever(s) in that position, line up the new stick of RAM -- there's a slot cut into the edge with the electrical contacts that must line up with the socket -- and then just press the RAM stick into place. The lever(s) should move on their own into the locked position once the RAM is fully seated. There are 4 screws holding the power supply in place at the rear panel of the case. Otherwise it's a matter of unplugging all the cables. The 2 connections to the motherboard, and one or two connectors at the graphics card [if there is one] all have latches on the side of the connectors that need to be squeezed to be able to unplug them. Note that what may look like one connector is actually 2 connectors side by side, and each will often have it's own latch. Installing the new power supply is basically just the reverse -- the most time consuming part is often routing & tying up the cables. Note that many motherboards have 2 power connections in the upper left corner, but not all power supplies have cables with connectors for both. Check the motherboard documentation, but generally you only need power to one of the pair. If you want to plug in 2 connectors but only have one cable, you can buy adapter cables with a matching power connector at one end, that connects to a cable with a 4 pin Molex power connector.
If there's a video card already in place, it can get tricky to remove it. That's because there's a latch at the end of the card slot towards the middle of the board. After removing any power cables & the attaching screws -- there's usually 2 -- you have to hunt for that latch and release it before the graphics card can be pulled out of the slot. Checking the motherboard documentation will hopefully show you how to release the catch -- the design varies from one make/model to the next. Adding a new graphics card is again basically the reverse -- if there is no graphics card you'll have to remove usually 2 slot covers at the rear of the case.
Adding &/or replacing drives can get slightly trickier because there are more options. If you want to add one or more M2 drives, check the motherboard's manual for locations and possible limitations, e.g., using an M2 socket may disable one of the card slots. If there's an M2 heatsink it'll have to be removed 1st, usually just a matter of one or two screws. The M2 SSD itself is a circuit board with electrical contacts at one end & a screw hole at the other. With the end with the screw hole raised, the end with the contacts should just slide into the socket. Then you press down the end with the screw hole and insert the tiniest screw I hope you ever have to deal with. If you're replacing an M2 drive bear in mind that it's slightly spring loaded -- you don't want it to pop up when you unscrew that screw and send it flying. How you physically mount an SATA 2.5 inch, 3.5 inch, and optical drive is up to the designer / manufacturer of the case. You may or may not be able to physically add one or more of those 3 types / sizes. If you're adding a drive you'll need to supply it with power, so you'll need an available cable from the power supply with the appropriate connector, you'll need an available [unused] SATA port on the motherboard, and you'll need an SATA cable for that connection. SATA cables may have a metal latch or lock on the top of the plug that has to be depressed before you can unplug it. If you're adding a 2.5 inch SSD, or replacing a 3.5 inch conventional hard disk with a 2.5 inch SSD, you might need a mounting adapter to fit the smaller drive in the larger space. If you don't have the available power cable, you can buy Y cables to get 2 connectors from one. If you don't have an available SATA plug on the motherboard you'll have to buy an add-on card with SATA plugs. Both the SATA and power cables will only plug in one way. When routing SATA cables avoid severe bends, using gradual curves as possible.
You may be able to replace the CPU cooler and/or the CPU, without taking everything apart. To replace the CPU the existing motherboard must support the new one, while replacing the cooler without pulling the motherboard depends on how it's mounted. All CPU coolers are mounted to the motherboard so that it makes tight contact with the CPU for optimal heat transfer. Sometimes the cooler uses a custom mount that requires its own backplate, a rectangular support on the backside of the motherboard. Some cases have a cutout so you can replace that backplate without pulling the motherboard, but if your case does not, and the cooler requires its own backplate, you'll have to pull the motherboard. Check the cooler's installation instructions to see how to remove, & reinstall it. Note that sometimes the cooler will stick to the CPU because of the thermal paste used, so you might have to wiggle it a little and apply some slight force. Have some alcohol cleaning pads ready when you detach the cooler, and immediately clean as much of that paste as possible off both surfaces -- if you let it that paste will get Everywhere. You'll find directions on replacing the CPU with the CPU's packaging, in the motherboard manual, and in online tutorials & videos -- it can be helpful to see how it's supposed to look, so you can better identify any manufacturing problems with the CPU socket that could prevent the CPU from sitting like it's supposed to. You basically lift the latch on the socket, lift off the old CPU, then lay in the new one aligning the marks on the CPU & socket, then close the latch. If it's a pin-type socket, e.g., AM4, make sure the CPU is all the way down. If you're using a new cooler it probably came with thermal putty already applied. If not, apply thermal paste per the directions that came with it and then attach the cooler per its directions.
For more involved upgrades where you replace the motherboard, or if you're building a new PC, you want to start with a clean case with the side panels and anything else that would make it easier removed. If you're upgrading, meaning you're reusing some parts, it's still often worthwhile to remove everything so you can clean the case fans for example, &/or blow out the dust in the power supply etc. Dust tends to breed faster once it gets a foothold, and will eventually get to the point it hurts airflow & cooling, so start fresh / clean. Disassembly is usually pretty straightforward, with the hardest part often removing things like a front panel that snaps into place using plastic prongs that have to be squeezed together to remove that panel. If you're removing the motherboard for an upgrade you can usually leave an air cooler, the CPU, any M2 drives, and the RAM in place. Just disconnect all the cables, remembering the power supply & SATA cables can have catches that have to be depressed. Remove the graphics &/or any pci cards if you have them, and remove the rear case fan(s) since those always get in the way. Remember that the graphics card probably has a latch or catch at the rear of the card slot. The motherboard itself is usually held in place by 3 rows of 3 screws each -- remove those and it should lift out. Note that the I/O plate, where the rear USB ports etc. are, may be separate from the motherboard. If that's the case, those often use springy steel fingers to ground the panel electrically with the board, so you might have to move the motherboard away from the rear of the case before you can lift it out. Then I like to set the motherboard on a piece of cardboard on a table or other flat surface -- you don't want to scratch the backside of the board, which could damage it, or damage the table because there are many sharp points where components are soldered to the board. With the motherboard out it's easier to remove the cooler, CPU, any M2 drives, the RAM etc. to either store or reuse.
Putting everything together.
If you're using a new case the offsets the motherboard mounts to may be in a plastic bag. The offsets are like small screws with a tall nut instead of a screw head. If you buy a new case it may have more screw holes for offsets that you need in different patterns to match different board standards. The offsets just screw in & do not have to be super tight [the sheet metal may be too thin to get them super tight without damaging the threads] -- I just make sure they're snug using a pair of pliers. At any rate, look at the board's mounting holes and look at the installed offsets and they should match. You'll want to install the case fans, with the exception of any fans on the rear case panel, and then usually the power supply. The power supply is heavier, so you don't want to slip and drop it on the board. If it uses modular cables you want to plug in the ones you'll use before you mount the supply using 4 screws at the rear of the case -- it's easier. If the motherboard uses a separate I/O plate, you want to pop that into place. And if you're using water cooling, it *may* be easier to mount the radiator now -- they generally mount using precut holes for fans in the case. And depending on the case design, it may be easier to mount any 2.5, 3.5, &/or optical drives now.
Next carefully inspect the motherboard for any damage or manufacturing defects, e.g., check the CPU socket for extra plastic from the molding process. Assuming everything looks good, & in any order, install the CPU, any M2 drives, RAM, and as necessary, the backplate for the CPU cooler. If you're going to use an air cooler for the CPU, it may be easier to install it now rather than when the board's mounted, depending on how big the air cooler is. Note that there are usually 4 RAM slots, but most people buy a set of 2 sticks of RAM. Check the motherboard manual for which slots to use. Note also, the number and speed of M2 sockets varies, plus using one or two of the available sockets often results in reduced speeds for one or more pci card slots. Read the manual to help determine which M2 sockets you use.
With the motherboard now ready you lay it into place on top of the offsets -- if it uses a separate I/O plate you'll have to push the board against that plate for the screw holes to line up. Insert & start, but don't tighten 2 or 3 of the mounting screws. You'll also want to check the ports at the rear to make sure that one of those fingers didn't get bent & is blocking a port if it uses a separate I/O plate. Once everything looks good start, but don't tighten the rest of the motherboard attaching screws, then when they're all in place, and you won't have to shift the motherboard to get the holes to line up, go ahead and tighten them -- they should be snug but do not have to be super tight. I think the hardest part of connecting the motherboard is plugging in the switches & LEDs from the case. Some motherboard brands, e.g., Gigabyte, may supply a separate connector that you plug the wires from the case into, then plug that larger connector into the board. That helps. Otherwise, you'll see 2 rows of pins on the lower right corner of the board, you'll have 6 or 8 wires from the case, often with each wire having it's own small connector, and going by the motherboard's manual, you have to plug the right wires onto the correct pins. You often have very little room, depending on the case design, so I like to get that out of the way 1st, before anything else can get in the way. Cases also often have an audio jack up front, and that means another batch of thin wires, though these should be connected to a small plug. Referring to the manual, plug that one in next -- the socket is usually on the bottom edge of the board, and depending on the case, can be hard to plug in because of little to no room. The same can be said of any fan sockets along that bottom edge -- it can be easier to plug in any using those lower edge sockets now as well.
Next I'll plug in the main power supply cables because they're usually thicker & less flexible -- the other cables can be more easily routed around them. If you haven't mounted an air cooler yet, but intend to, plugging in the cable on the upper left of the board beforehand is easier. Once that's done, the CPU cooler can be mounted at any time. The thickest, main power supply cable that plugs into the right side of the board is the hardest to work with -- you'll generally get it to fit, and however the cable's routed that's it, everything else will have to go around it. If using a graphics card, lay the power cables for the card more or less in place, so you can route the other cables around them, but you usually want to insert any cards themselves after you've got the wiring done, because they can block access. Earlier I wrote that SATA cables should not have severe bends, so it's good to install them now, connecting any SATA drives -- the remaining cables can go around them. Now, referring to the manual, plug in any USB cables from the front of the case, the power supply cables to any SATA drives, fans, and if used, any RGB lighting. If you haven't yet, mount the CPU cooler to the CPU, plug in the cooler fans &/or pump, mount any fans to the rear case panel, and finally, insert any pci cards, fitting them into the card slot(s), attaching them at the rear of the case with screws.
Routing and tying up all those cables is one of those things you just do the best you can. Many, sometimes most cables can be run along the backside of the metal panel the motherboard mounts to. Some cases have more room on that backside, some have more places to use plastic ties, and some even have wire guides and Velcro straps. Some power supplies use flat ribbon cables, while others are fatter & thicker. Having everything as neat as possible matters to some people more than others, but regardless, you want to do your best to try and make sure that cables are not blocking air flow across the motherboard, in front of any conventional hard disks, to the power supply, graphics card etc. It's not uncommon to have to apply a little pressure to get the case panel back on because of all the wires, but use common sense -- if you have to sit on that panel to get it to close you've got too many cables in too small a space.
You should now be ready to plug the PC in, connecting the mouse, keyboard monitor, power cable etc. Whether you leave one or both side panels off initially is up to you -- you may find that you got the polarity wrong for one of the case LEDs for example, and have to switch the wires around, and if the side panel's already off that saves you a minute or two. Make sure that the switch on the power supply at the rear panel of the PC is turned on, and start the PC. It will take a short while as the BIOS takes inventory of the connected, installed components, and then you'll normally see the BIOS setup screen -- otherwise you get into the BIOS setup menus by pressing *usually* the Delete or F2 keys when the PC is just starting up -- the hotkey used can vary. What you'll see in the BIOS setup menus varies by motherboard manufacturer, and to some extend, with the board model. The manufacturer may document the BIOS settings, or not, and you may or may not be able to find anything in reviews of that motherboard. When you select a setting you may or may not see a brief explanation of that setting. It can help to have a phone or another PC handy to Google any terms for settings you're unsure of. Most settings will have an Auto option selected by default & that will usually work, but there are exceptions. When you buy RAM it's normally sold using the speed rating of it's built-in overclocking profile, but that profile usually has to be set in the BIOS to be turned on -- otherwise the RAM speed will be sometimes much lower. Different board manufacturer's can use different terminology for the setting where you turn that on. Virtualization support, TPM, & Secure Boot may need to be turned on. You will likely have to select the drive where the BIOS should look first for the boot loader. If you're using a graphics card you may need to turn off the built-in GPU to avoid problems in Windows. Hot plug support may be turned on for the drives, and you may need/want to turn that off. Needless to say it's common to have to go in and tweak those BIOS settings, often more than once, once you get Windows running.
If you're using an existing copy of Windows, rather than installing a copy fresh, it should adapt on its own to any different hardware, but you'll want to run the setup routine for any drivers, e.g., the chipset & GPU to make sure everything's setup properly. Note that switching from one AMD CPU to another you may find that it's recommended to install Windows fresh, depending on the CPUs. You'll also want to run Device Mgr. have it show hidden devices, and right-click -> uninstall leftovers from the old motherboard.