windows xp user group

hi!
a user of a pc in a network deleted the access to his folders by adminitrators. he cannot login to the net anymore. logging on with the local administrator didn’t help because the admin has no access to the profile and somhow has also no access to the “users and groups” stuff. attempts to modify it there doesn’t work. the users and groups area has a huge red cross and clicking onto it returns something like- library not created or accessible.
any help guys?
cheers