I am sure at some-point everybody has been resolved to using a shared open access computer in a school or library where the desktop is messed-up, there is an error with every program action and it is filled with Spyware, but all access to the settings that could fix the system or simply change the wallpaper or screen resolution is locked by the administrator who is nowhere to be seen.
Well those days are almost gone as Microsoft is about to release Shared Computer (Beta download Here) which allows a user to do whatever they want to a system, because when the computer is rebooted those changes are erased and the whole system is put back to a state before the user changed anything. It does this by saving the changes on a hidden partition that is then erased when the system is rebooted.
The danger with this is that a user can't save any work on the computer because after the system restarts the work will be gone, but for keeping a computer as functional as the day it was setup, this is it. Shared Computer is currently free in beta form until the product is launched in time for September when the schools reopen.