Procedure to Lock or Unlock the Power button on LP2151 monitors:
Press and hold the two left menu buttons on the front panel of the monitor (Example: O-O-X-X-X).
A gauge will be displayed on the screen stating "Power Button Locking" or "Power Button Unlocking".
Continue holding both menu buttons until the gauge is full and "Power Button Locked" or "Power Button Unlocked" is displayed.
Power button will remain in Locked or Unlocked state until the procedure is reversed.