Hmm... That's wierd. I would recommend taking it to a computer store, where you can have an expert look at the problem. We took ours to one not too long ago, and it costed about $40. But, I think that it was worth it because he installed several good Anti-Virus programs, and he took out TONS of un-needed files, etc. Our computer works better now. If you don't want to do that, then... Er, get Ad-Aware or something, lol. It does work to take out Spy-Ware and stuff. (Kazaa could've caused some of this.)
And if you accidently clicked one of those links when that spammer was posting porn, then it may have downloaded something then. Since, you mentioned that this all started a couple of days ago...