People listen to my words, run ad aware from Lavasoft.
Just today I ran it for the first time. I was actually certain that I didn't have any spyware installed on my computer, but boy - how wrong I was. 65 reg. entries were found and numerous programs that had infected my system. After cleaning that shit up, I noticed a faster boot time, and an overall faster and more stable system.
Trust me, run it for your own sake.
Download the standard version here