Actually, Lavasoft Ad-Aware should get rid of most. You may want to peek in Program Files. There's usually a StopPop or ClrSch folder lurking around even after all the scans. Best thing I can thing of is take it to somebody that knows what to look for in the registry. Most of that shit is set into the registry so even if you delete the files, it comes back. Make sure to manually dump C:\Windows\Temp, Temporary Internet Files, etc. The temp folders is where the installers usually hide, and are then called again from the registry. Between that and all the scans you've run, you should be in the clear soon. Hope so anyway!
Scottie