Forget the big name programs and their fancy interfaces, etc. Just run combofix, a good old command prompt program that many IT professionals and networking security guys use to take care of spyware/malware in one go. It is simply the best I have seen for dealing with the most serious problems.
http://icrontic.com/forum/showthread.php?t=55039
If you aren't comfortable with that, then Spybot S&D is probably the best out there. Make sure you update, the tea-timer is a good system protection if you don't mind the registry warnings, after you clean your system make sure to immunize. If there are any items that fail to be fixed, look them up and get rid of them manually.
http://www.safer-networking.org/index2.html
I would recommend you run both.