To turn off the lcd (color) screen, hit the home button (on the bezel, next to the trackball - it's an icon of a house) and then press the large X on the bottom right of the screen. There will be three large icons in the middle bottom of the screen - press the lock icon in the center. That will turn off the lcd screen. To turn it back on, press any of the four buttons on the bezel, around the trackball. Then press the MENU button.