We have the same profile for all users (pupil). We enforce this by using a piece of software called Ranger, its just and easy way of using group policy. All our desktops are the same and the users can't right click anywhere so they can't change wallpaper etc. When they click on Start they only get Programs, list apps for each suite, and Logoff. They only have access to shared area and their own area on the server (they can't use \\ to get to server either).
Have found a piece of software called Browse Control that allows easy and instant access or denial to the internet (doesn't need machine to be restarted users just have no access instantly even if they are already browsing) to either individual machines or a whole suite when placed in a group within software. Also includes web site blocking and app blocking.
I'll take a look at Deep Freeze sounds interesting.
Mattwary - Thanks, I'll see if I can use some of your scripting