Have you tried this tool:
http://www.bitdefender.com/VIRUS-157247-en–Win32.Brontok.A@mm.html
Try a few rootkit scanners and see if they find anything:
http://www.f-secure.com/blacklight/
http://www.antirootkit.com/software/Panda-Anti-Rootkit-Tucan.htm
Could you post a HijackThis! log for us to look at?
http://www.bleepingcomputer.com/tutorials/tutorial42.html