get HiJackThis
Look for anything suspicious - get it to make logs etc. - boto up in safe mode and redo - delete entries writing down specific locations of the files, delete them if possible... if not leave it for now...

reload OS normally and everything should be hunky dory - if the files are still there they should be able to be removed. if not look for "rundll32.exe" in task man, perfectly harmless.. normally..