blocking user from using internet explore

one of my computers is running WindowsXP Pro, and I am trying to stop a user from using ie. So far I have setup a non-administrator user account and I have blocked ie from opening in the group policy editor. I have also tested to make sure that the block is working. I tried opening ie from its shortcut, through its program folder location, and even tried running it as an administrator. After doing this test, all tries were successfully blocked. however, this guy was still able to open ie. did I miss something? How is this possible?

Dup - see http://forums.whatthetech.com/index.php?showtopic=126434