First I would make a restore point to ensure if you damage windows it can be recovered, it does not hurt to backup your files as well. I would also change settings on making Hidden Files visible so the Spyware scanners can find everything.
I would run AVG Free and Spybot S&D first to clean up your computer. Use Spybots Immunization feature, it can help you not get infected. If Spybot does not get it all, or locks up, I recommend SUPERAntiSpyware for the next portion of the cleanup. Stupid name, great program.
Finally, I would run CCleaner to tidy up your computer. Check what settings your playing with of course before you clean anything up. It really can clean up those temporary files well, along with making allot of your browsers history disappear as well.
Good luck.