Gregg OH1

When I double click or try to merge my CCleaner reg backups I get a pop up saying windows cannot find command.exe which is needed to open registration files. Running Win2000pro service pack4. I ran spybot,avg,anti rootkit,etc, nothing found. Everything else seems O.K. Uninstalled,reinstalled CCleaner, created new backup and cannot merge it either! Thanks 4 any help!