How do you  lock a computer monitor?
 1. Power on the monitor. 
2. Press and hold the MENU button for at least 15 seconds. 
3. Look to see if a LOCK icon appears on the screen. 
4. Release the MENU button and wait 5 seconds. 
5. Press any button on the monitor to test. 
6. Turn off the monitor if it is no longer needed. Basic Unlocking Procedure. 