This tutorial will show you how to enable or disable the ability to lock the computer (Win+L) for all users in Vista, Windows 7, Windows 8, and Windows 10. If you disable lock computer, Lock will also be removed from the Start menu, Power menu, Ctrl+Alt+Del screen, and Alt+F4 Shut Down Windows locations in Windows.
https://www.tenforums.com/tutorials/84631-enable-disable-lock-computer-windows.html