On my MID7012, this has happened about four or five times. I'll be using the tablet vertically and the screen will suddenly switch to landscape orientation, then the screen goes black as if it's shutting off, and a while horizontal line appears briefly just as it's shutting off. It will not come back on by itself, but if I push the power button, the screen comes back on. It seems like a hardware problem, but I'm not sure. Has anybody else experienced this? Also, I have the screen timeout set to 30 minutes, so it wouldn't have anything to do with that.