A friend asked me to block a website on his computer, and not tell him how I did it. He knows about the hosts file, and ends up just unblocking the site himself if it's blocked from the hosts file.
Is there a simple way to block a website that my friend (who is average as far as tech literacy goes) won't be able to easily reverse? I'd prefer not to install invasive child-monitoring software if possible. I believe he's running Windows 7.
Edit: He's a student, and is on-campus pretty often. I think he has control over his home network, but just blocking it on his home network will only be mildly helpful.