My two favorite spyware removers are
Ad-Aware and
Spybot. I also like to use
HiJack This as well; it operates differently, and isn't as user-friendly. I would install the latest versions of all three of them.
If it's only happening on one account, it may very well be spyware. Try cleaning from the infected account, and then try from an uninfected oned if the first one fails.