Disable the Log Off and Turn Off Buttons in Windows
Contributed by Raj 
October 13, 2004 
Tagged: Windows security
Do you support users who, regardless of what you tell them, insist on logging off or shutting down public computers in common areas?
If so, you’ll be glad to know that you can disable the Log Off and Turn Off Computer buttons on the Start menu.
Follow these steps:
Open the Registry Editor (Regedit.exe).
Navigate to HKEY_CURRENT_USER\SOFTWARE\Microsoft\ Windows\CurrentVersion\Policies\Explorer.
Right-click the Explorer key, and select New | DWORD value.
Name the value StartMenuLogoff, and press [Enter] twice to access the Edit DWORD Value dialog box.
Type 1 in the Value Data text box, and click OK.
Right-click the Explorer key, and select New | DWORD value.
Name the value NoClose, and press [Enter] twice to access the Edit DWORD Value dialog box.
Type 1 in the Value Data text box, and click OK.
Close the Registry Editor.
At this point, both the Log Off and Turn Off Computer buttons are still on the Start menu, so click the Log Off button and then log back on.
When you need to shut down the computer, launch the Registry Editor, and change the values to 0, or pull the plug if it has to be done in a hurry.