Recently my Rebel XTi's display screen has been turning off and on repeatedly in a very short amount of time. After turning the camera on, the display screen will "turn off" for about 1 - 5 seconds and then turn back on for 1 to 10 seconds then turn back off and this will continue for who knows how long. It's especially annoying when I'm trying to adjust a setting and the display screen has turned off, then turns back on for a split second (barely enough time for me to change anything) and then goes back off again. I can't do anything to the settings when the screen is flickering like this. The battery meter is still full. Does anyone know why this is?