Mine's a similar scenario but a bit terrible. I had the tablet cnnected to charger while using it then all of a sudden the screen went all black, keys at the bottom are still lighting up but non responsive. holding down power button didnt do anything. so I held the Power + Vol down button for almost a minute, then the tblet completely turned off.
Now i had to turn it back on. Held Power + Vol DOWN + Home, nothing. Held Vol down button, nothing. Held Power + Vol UP + Home, nothing. Im starting to think this is a battery issue. I've never had this problem since i purchased this tablet 9 months ago. so weird. now i have the tablet connected to the charger but even the battery charging status is not showing. Tablet is completely turned off. If this is still the case tom i will bring the unit to the store for repairs. Unless you guys can provide me any other solutions. Thanks.