Disable and remove the Shut Down command
User Configuration\AdministrativeTemplates\Start Menu & Taskbar
Removes or disables the items that let users shut down or restart Windows 2000.
This policy removes the Shut Down option from the Start menu and disables the Shut Down button on the Windows Security dialog box that appears when you press CTRL+ALT+DEL.
In Certified for Microsoft Windows programs, this policy disables or removes features that let users restart or shut down the system.
If you disable this policy or do not configure it, the Shut Down menu option appears, and the Shut Down button is enabled.
This policy was documented incorrectly on the Explain tab in Group Policy for Windows 2000. The Explain tab fails to mention that this policy affects Certified for Microsoft Windows programs.