Samsung SyncMaster 740BX Owner's Manual page 24

Menu
After pushing the "MENU" button more than 5 seconds, OSD function is
locked (unlocked).
Locked
MagicBright™
Menu
Push the MagicBright™ button to circle through available preconfigured
modes.
MagicBright™
- Six different modes (Custom/Text/Internet/Game/Sport/Movie)
Description
You can also adjust the brightness and contrast of the
monitor with the OSD adjustment locking feature.
Description