This is a simple Computer Trick which is used to disable the Turn OFF options Like Shutdown Menu , ALT+ F4 etc.
Follow these simple steps.
1) Go to START MENU. In it, Open RUN.
2) Type Regedit and press enter.
3) Then in Registry Editor Window go to HKEY_CURRENT_USER/Software/Microsoft/Windows/Current Version/Explorer.
4) Now in the right pane right click and create a new DWORD item and name it NoClose.
5) Now modify it’s value and set it to 1.
6) Restart your system .