Thanks for the help guys, unfortunately the router is two rooms across from me so a wired connection is not possible. :( Thanks for suggesting that build to me, I will probably go with it :)
First of all get 8 gigs of ram, 2x4. Get an i5 instead of the FX CPU, AM3+ Motherboards don't have an upgrade path.
If you aren't doing any overclocking no need to get the Hyper 212.
If you don't care about the files on the computer reinstall windows, If not boot in safe mode, run all the scanners you can think of, run Ccleaner, reinstall Firefox, and you should be good :)
If you don't care about the files on the computer, nuke it with reinstalling windows. Read this article: http://www.pcworld.com/article/243818/how_to_remove_malware_from_your_windows_pc.html
http://pcpartpicker.com/p/LxjxCJ Best I could do, not sure bout the graphics card not having a series.
Much Better build without OS: http://pcpartpicker.com/p/H6dQNG
Worst CPU ever for that graphics card, there would be a massive bottleneck, these guys builds above ^ are great. I am inclined to go with Raiins build because he doesn't have the XFX graphics card, they tend to get quite hot.