U can try this on ur friends PCs... (I tried it on my college's H.O.D.'s PC remotely through network. He dumbly formatted all PCs in our college.
)
Go to regedit, then go to
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
Here, create a new DWORD value called 'NoClose'
Open it, and change value to 1.
Now 'Shut Down' will not be available in Start Menu. Works with all windows versions.