Reason # 69 for not visiting p*rn sites: your computer gets infected with all sorts of spyware and pop-up advertisements and you can't get rid of them even after you've downloaded the most recent version and run SpyBot five times.
Any other freeware I should try?
UPDATE: I downloaded AdAware and after two hours, one unintended nap, 200,000+ files scanned and 199 critical objects found, I thought I had resolved the problem. Performance seemingly back to normal, but wouldn't you know - I'm still getting the damn pop-ups! And there is this annoying search box that keeps peeking up from my bottom taskbar. Grr. I'll keep working on it.