If the tablet is under warranty, I would contact your service provider or the manufacturer to have the device repaired or replaced. Why? Wel doing many things to resolve this may well void the warranty, so it is best to go through them if you can.
Now if you are out of warranty, the first thing I would suggest you try is to locate the "Reset Button" on the device. It should be a little pinhole either on the edge or where anything plugs in (cord, card, etc.,) to the device. Using something small (like a pen tip) depress the "Reset Button" to do a "Factory Reset". Do not use anything sharp (like a pin) as you can damage the device. Note: You 'may' lose some data on the device when doing this.
You can also just let the device run down...