This policy setting prevents users from starting Task Manager.Task Manager (taskmgr.exe) lets users start and stop programs; monitor the performance of their computers; view and monitor all programs running on their computers including system services; find the executable names of programs; and change the priority of the process in which programs run.If you enable this policy setting users will not be able to access Task Manager. If users try to start Task Manager a message appears explaining that a policy prevents the action.If you disable or do not configure this policy setting users can access Task Manager to start and stop programs monitor the performance of their computers view and monitor all programs running on their computers including system services find the executable names of programs and change the priority of the process in which programs run.
System\Ctrl+Alt+Del Options
User
At least Windows 2000
HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System!DisableTaskMgr
CtrlAltDel.admx