Computer is all messed up...?

Ok I downloaded Grand Fantasia played it for a bit and then uninstalled it. I downloaded it into my Program Files and uninstalled it there too. I realized that all the files weren't in a folder. After the uninstall almost all my programs were gone. I system restored but that only brought a few back. I can't uninstall anything that is "broke". Firefox doesnt work, Java doesnt work, Aion doesn't work, and even AVG didn't work. At first I thought this was a virus, but I eventually found out that this was my doing. Anything I can do to get back the missing files or even uninstall things so I can reinstall them? Plz help!