At the time, the phone was on. The screen went black (but stayed lit up) and then powered down. The screen itself cracked, but did not shatter. Since then, I've been unable to power it back up or perform a factory reset. The phone gets warm and vibrates every couple minutes if plugged in or if it has power from being recently plugged in. If I can't fix this problem at home, I don't mind taking it in to get it done as it's insured, but if that's the case I'd prefer to at least wipe it first. I've tried the typical factory reset/boot menu actions (hold volume down and then power, hold power, etc.) but nothing has given me any sort of reaction besides the phone vibtating. Any tips?