Solution #1
1. Make sure the display is on.
2. Now, press and hold the Power and Volume Down button at the same time for around 10 seconds.
3. Victory! The device should now vibrate and reboot.
1. Begin by removing the rear cover and, later, the battery for a few seconds.
2. After a moment, put them back in/on.
3. Lastly, turn the phony on by holding the Power button.