To turn the phone on, press and hold the Power/Lock button until the screen lights up.
To turn the phone off, press and hold the Power/Lock button.
Tap Power off.
Tap POWER OFF.
If you are unable to turn your phone on, plug the phone into a power source for 15 minutes, then try again.
If you are unable to turn your device off with the Power/Lock button, remove and re-insert the battery. Note: This performs a simulated battery disconnect.