This policy setting prevents users from performing the following commands from the Start menu or Windows Security screen: Shut Down Restart Sleep and Hibernate. This policy setting does not prevent users from running Windows-based programs that perform these functions.If you enable this policy setting the Power button and the Shut Down Restart Sleep and Hibernate commands are removed from the Start menu. The Power button is also removed from the Windows Security screen which appears when you press CTRL+ALT+DELETE.If you disable or do not configure this policy setting the Power button and the Shut Down Restart Sleep and Hibernate commands are available on the Start menu. The Power button on the Windows Security screen is also available.Note: Third-party programs certified as compatible with Microsoft Windows Vista Windows XP SP2 Windows XP SP1 Windows XP or Windows 2000 Professional are required to support this policy setting.
Start Menu and Taskbar
At least Windows 2000