Try to run a few of these. Like ramblux says, they all pick up and remove different spyware/adware so for best results use at least two of them.
Lavasoft Ad-Aware:
http://www.lavasoftusa.com/software/adaware/
Bazooka scanner:
http://www.download.com/Bazooka-Adwa...-10247782.html
Spybot search & destroy:
http://www.safer-networking.org/en/download/index.html
A few more links to other spyware/adware scanners, and some light reading...
http://www.f-prot.com/support/windows/fpwin_faq/13.html
GL