This policy setting prevents users from locking the system. While locked the desktop is hidden and the system cannot be used. Only the user who locked the system or the system administrator can unlock it. If you enable this policy setting users cannot lock the computer from the keyboard using Ctrl+Alt+Del. If you disable or do not configure this policy setting users will be able to lock the computer from the keyboard using Ctrl+Alt+Del. Tip:To lock a computer without configuring a setting press Ctrl+Alt+Delete and then click Lock this computer.