Hello, I have a 13" MacBook Pro that I bought in September of 2010, and I am now experiencing a problem with the monitor. When I dim the screen all the way down, it will stay black for a few moments but then it will come back on to the lowest setting. When I move the mouse, the screen goes back to black as if the computer didn't know the screen had come on again. I have to press the brightness button once to return it to the lowest setting. I have tried restarting my computer and all the updates are installed. Please advise. Thank you.