Hello,
This just happened to my Nextbook. This worked for me like a charm.
1. You have to take the back cover off first.
2. Look for the power connector (it's white leading from the battery).
3. You have to carefully disconnect the power connector from the tablet for 25 seconds.
4. connect it back like it was . i was able to power it up with not problem .
I would probably charge the battery before attempting , it may not make a difference .
the back cover is pretty easy to take off.
feel free to drop me an email if you wish ... malcolm.powell@mycomputerbackups.com