There's a partition mgr. app today on GOTD, IM-Magic Partition Resizer Pro 2013, and unfortunately a bit of misinformation in the comments. It would be useful if I or anyone else could say IM-Magic Partition Resizer Pro 2013 is a great app or a POS, but it takes a fair amount of using a partition app before anyone can say whether it's good or bad IMHO, so grading it one way or another is likely to just be whomever's unsubstantiated opinion. IM-Magic Partition Resizer Pro 2013 is missing some features found on some other partitioning apps, but since most people don't use, or don't need to use those features anyway, that's not a reason for me to say don't download & use it.
As far as the misinformation part goes, there's plenty of [IMHO way overdone] warnings about the dangers & complexity of working with partitions. For some reason that remains unfathomable, lots of people have yet to embrace the concept of disk/partition image backups. The software's free. If you can't afford ~$50 for a 2nd, internal or external drive, you should be able to afford ~$14 for a DVD burner [if you don't have one already] & ~$0.18 per blank DVD disc to store your backups. And once you've backed up the contents of your hard drive that way, working with the partitions on that drive is for the most part risk free -- your only risk is you might have to spend the time to restore a backup or backups. There's no mystery, no vast knowledge required, no big risks.
Likewise there's a comment not to use a Windows-based partitioning app. Balderdash!
At any rate, please don't believe everything you hear or read or see. If/when I post something I'll say when I'm stating an opinion, & everything else can be [I hope :) ] reinforced or corroborated via Google. I try not to hint that I'm correct simply because I've some sort of expert knowledge or anything -- the more you know the more you know you don't know. :) And it bothers me when someone else takes the road I prefer not to -- it bothered me enough to repeat again some few partition basics. I hope you'll forgive me if, because this has all been posted before, it's simply redundant.
As I posted in the GOTD comments...
FWIW...
Working with partitions isn't dangerous, isn't rocket science, isn't just for expert techs etc., *As Long As You Have A Backup You Can Restore*.
You can't move, alter, or delete files while they're in use -- this includes the files where Windows' registry is stored -- disk/partition image backup apps [e.g. Paragon's] backup an snapshot of those files, reflecting what they looked like at that particular moment. That means you can't carry out every type of partition modification to the system partition [where your running copy of Windows lives] while that copy of Windows is running. And that means that the biggest difference you'll often see using a Windows-based partition app vs. a *nix-based solution like GParted [ http://sourceforge.net/projects/gparted/ ], is you can set up your partition jobs or tasks in Windows, then perform them during a re-boot, rather than just re-booting into another environ from the start.
A Partition is simply how a hard drive is divided up. You add folders to *divide up* what you see as a hard drive in Windows -- you add partitions to divide up a physical hard drive into the hard drives Windows sees. A hard drive may just have one partition, e.g. C:, or several, e.g. C:, D:, E:, F: etc. The main difference between creating a partition & a folder is you allocate some of the hard drive's storage space when you create the partition -- that's what makes it more complicated.
Once a partition includes data, you copy or move that partition including all data stored there. When you want to reduce the size of a partition [usually to make room for a new or enlarged partition elsewhere on the drive], you have to make sure that shrinking that partition's boundaries doesn't delete all or portions of files -- assuming you want to keep that data... if you're for example going to re-install Windows, you'll just do a quick format rather than bother about any existing files. You can preserve existing files by either moving the files to other storage 1st, or by concentrating them all towards the partition's starting boundary, leaving just free space at the end boundary you're going to be moving to shrink the partition.
Many partition apps offer a feature to move a partition's data for you. A decade or so ago disk/partition image backup apps, along with the means to store backups, were much less common, were much more expensive, and having a partition app move your data was a workable, not to mention easier & cheaper solution. But now is now... Having a partition app move your data when/if necessary basically just saves users from learning how to use image backup software -- nothing more.
You should backup a partition before moving or altering it. Once you have a partition image backup, you can restore that backup anywhere, to any size partition, as long as the destination partition has enough space to fit the files in your backup. That means for most people a partition app is just a means to set the partition boundaries on a physical hard drive. A partition app's measures to protect or guarantee the integrity of your files or data is irrelevant -- you guaranteed that when you performed the backup.
And all that also means that for most people brand X vs. brand Y partitioning apps isn't such a big deal. Yes it can matter is you're getting into RAID or dynamic disks & so on http://windows.microsoft.com/en-us/windows-vista/what-are-basic-and-dynamic-disks .
As far as why partition... From win95 through win8.1 lots & lots of Windows files have & use the same file names, even though the files themselves may be vastly different. The easiest way to have Windows use the right ones is to put each Windows version on a separate disk, & as far as Windows knows, each partition is a separate disk. You can also use partitions the same way you use folders to organize your files... it makes life & maintenance simpler.