My bosses teenage children and their friends come into our office after hours and access the internet using our computers. We've got windows passwords to each individual computer but they've either figured them out, or we've heard that they can access the internet via safe mode if they can't log onto windows normally. We'd like to know if there is a way to totally block access to the internet when we aren't here... Or to ensure they can't get on Windows via safe mode. Personally, I'd rather stop them from using the computers at all if possible.
(I wish it was just as simple as telling them to stop and they would, but no such luck... please help if you can, its getting out of hand with them sometimes changing settings, installing unwanted programs and games, etc.)