pressing the power button for about 20 seconds should force it to power down. If not you can try letting the battery run out and recharging and see if that will get it to unfreeze. If not it would need to be replaced.
pressing the power button for about 20 seconds should force it to power down. If not you can try letting the battery run out and recharging and see if that will get it to unfreeze. If not it would need to be replaced.