PC Services Optimizer Pro basically changes the registry entries for various services to disabled under Computer\ HKEY_LOCAL_MACHINE\ SYSTEM\ CurrentControlSet\ Services\. It has an auto mode where it first asks you several yes/no questions to help determine what it can turn off -- when you're done it will set a restore point, show you a preview of what's being turned off, then assuming you agree, makes those changes. You can of course turn off services in Task Mgr, but that's more of a stop gap measure -- using Windows Services applet you can turn services off/on, or set a delayed or manual start, and those settings will persist until you change them... it's often been recommended to set a service that's taking up resources to manual, which means it's off, but will *hopefully* start if software needs it. That said, the 2 main reasons to bother turning services off, AFAIK, are to get max fps gaming, or if you have a Really low end CPU, e.g., one of the Intel Atom chips [the cheapest, Slowest chips Intel Makes].
Installing PC Services Optimizer Pro gets you the program's folder, a folder in Users\ [UserName]\ AppData\ Local, 3 folders in ProgramData, and an estimated around 200 new registry entries [guessing at how many cache entries there were in my VM]. There were some questions in the comments on the GOTD download page about activation... there's a URL in the readme.txt file -> go there and after solving a CAPTCHA you'll see a code for activation. The app itself has a link to register on the lower right -- click that and you'll get a window with spaces for name, email, and that key.
