Edit the registry. Navigate to the following sub key: HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System In the right-hand pane, locate "DisableTaskMgr" and modify the value to 0. And Navigate to this following sub key: HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System In the right-hand pane, locate "DisableTaskMgr", if present, and modify the value to 0.