Hello. I wonder if anyone can help me? I left my son's tablet charging last night and this morning I found it with a frozen screen. Please see the picture. I have read various methods on how to restart it but nothing works. I pressed the power button and volume down at the same time, the screen went black and I can't start the tablet. It's on the charger right now just in case, but it doesn't work. I tried booting with the power button and volume up, nothing. Any advice on what to do please? Many thanks.
