Run gpedit.msc, User Configuration|Administrative Templates|Control Panel|Display - Hide Settings tab (enable this policy).
This will affect you too (you can turn it off if you want to change display, then turn it back on - or see here - whoops link not working any more, I'll have to find another. Link was to a site giving instruction to exclude Administrator account from policy lockdowns). Also, obviously if other users have admin rights they can turn this off too.