Limited Access (Score 0)

Basically, only allow him to access content when you're there. Be the only one to have the password to access the computer and only allow him to access when you're around. As someone else has already suggested, keep it in a common area. If you're going to allow him to have a personal email account, keep the password yourself, and only allow him to get to his email when you log him on. That also lets him know that you have full access to his account and address book. Finally, keep an eye on the browser history, if it's being wiped regularly by him, that means he's hiding something.