Try unlocking it:
1) Press the MENU-button ( ) to activate the OSD window.
2) Press or to navigate through the functions. Once the desired function is highlighted, press the MENU-button to
activate sub-menu . Once the desired function is highlighted, press MENU-button to activate it.
3) Press or to change the settings of the selected function. Press or to select another function in sub-menu .
Press AUTO( ) to exit . If you want to adjust any other function, repeat steps 2-3.
4) OSD Lock Function: To lock the OSD, press and hold the MENU button while the monitor is off and then press power
button to turn the monitor on. To un-lock the OSD - press and hold the MENU button while the monitor is off and then
press power button to turn the monitor on.
5) Eco Mode hot key ( ) : Press the Eco key continuously to select the Eco mode of brightness when there is no OSD (
Eco mode hot key may not be available in all models).
6) Volume adjustment hot key : When there is no OSD , press Volume ( ) to active volume adjustment bar, press or
to adjust volume ( Only for the models with speakers).