The Dell monitor connected to your computer contains a series of menu screens that let you change options such as the brightness, image position and color settings. If you want to protect the current settings, or prevent an option from changing if someone accidentally taps the wrong button, the monitor includes an extra lock feature. When you are ready to change any options, unlocking the monitor's menu is only a matter of tapping the appropriate button combination.
Locate the "Menu" button at the bottom of the Dell monitor. Tap the button to bring up the "On Screen Menu" (OSD) display.
Tap the down arrow key, located next to the "Menu" button, to scroll through the menu. Navigate to the option labeled "OSD Lock."
Press the minus symbol button at the bottom of the monitor to set the "OSD Lock" setting to "No." Tap the "Menu" button again to exit the menu.