My insignia NS-P16AT08 tablet keeps shutting off. I will use it for a few minutes, and then the button asking if I want to shut down pops up. If I cancel it it comes back a second later and shuts off after the third or fourth time. It then takes 5-10 minutes to restart, as it keeps shutting off again while it's trying to restart. It's gotten to the point that as soon as I start using it, it shuts down again. It's had a hard reset done, and that didn't help. What should I do?