Disable system restore and then reenable it.Not sure that will work with a password but it's worth a try. Directions are here.
Son had computer at college and came home with viruses. I installed and ran Avast. It could not do anything with all the Restore\TEMP files because my son was using a password to keep his files private. He can't open his side of the computer now because the password prompt no longer comes up. Does anyone know how to get into them? It's Win/ME