Hi there, I just received the C90A today. It worked fine until I press 'A' with a circle around it. I think it was 'Auto' on the brightness setting menu. When I hit the on / off button, the tablet seems to boot OK the 'Android' symbol appears as it usually does, but after that nothing happens. If I tap repeatedly on the power button, the home lock screen appears for no more than about ½ a second, but then vanishes again into a totally black screen its never around long enough to actually unlock the screen with a swipe. I tried rebooting the tablet, and again the 'Android' symbol comes up fine, followed by nothing more than a black screen, and the occasional ½ second flicker of the lock screen when I tap around on the on / off button. I cant find a way to deactivate this black screen! I also tried resetting by pressing the reset button at the back of the device. Please help!