Hey, whatever anti-virus software you try, scan in safe mode..

To go to safe-mode, restart computer and keep pressing F8 while it is booting..and select 'Run in Safemode' Seems you are not scanning in Safe mode ..

Try to find out the name of spyware/virus .. and google around for its cure..

smitfraud.exe is one good tool for some speicific virus.

NOTE: DONT TRUST ALL APPLICATIONS TO REOMOVE VIRUS... WHILE DOING SO - YOU ARE DOWNLOADING AND INSTALLING VIRUS INSTEAD.