This is my second M9 with the exact same problem. Screen won't light up, although periodically when I leave it on and stationary for an extended period, pick it up and wake up the phone with the power button the screen will light up briefly then go out again. The phone works otherwise, just can't see the screen without shining a bright light into the screen. I've already done two factory resets. Any help is appreciated. First phone was replaced under the Uh-Oh protection. Had this one less than 4 months.