Your computer is probably much like the one I use for downloading stuff via p2p. I used Kazza for a long time before I made the change to a couple other P2P programs out there. For the most part, and I know you aren't going to like to hear this, you are screwed. I had so much spyware installed on my system that no matter how many scans I did to remove the stuff it just came back time and time again. Adaware would go through and remove what it found, I would then go back and do another scan right after than and it found more crap, all of the same things that it found before.
Basicly you will more than likely just have to reformat and do a fresh install. Back up what you want to save and get it done.