I've just uninstalled a trial version of RegSupreme using "Add/Remove Programs". However, I'm left with a folder containing Reg.Supreme.exe. When I try to delete it I receive a warning that it "cannot be deleted: access is denied".
Assuming it's not a rights issue, one possible explanation is that it's running. Use Task Manager > Processes to check. If it is running, End Process and then delete the file and folder. This may mean there's a shortcut in the C:\Documents and Settings\[uSER]\Start Menu\Programs\Startup or C:\Documents and Settings\All Users\Start Menu\Programs\Startup which needs to be deleted.