Also when I try the 20 seconds n & power trick. It's stuck on an endless loop of turning on and off. Never makes it.
I also figured out part of the problem which is the battery is not holding charge. I slid in my sdcard (with 4.1.2) and checked settings with battery. It say's it was 100% but 0s on the battery.
As I've recently discovered, a faint glow isn't necessary for this problem. Try the 20 seconds power button, followed by 2-5 seconds to restart. You might have to do that cycle a couple of times.
I had the problem a couple of times. Display was off but the tablet was still on. Somehow it seems linked to the 'sleep' mode.