Hi
Connet charging pin into phone and hold phone in your hand for a while, as soon as the phone vibrates just long press the power button until you see the Microsoft logo appear on screen. Put the phone down and it will just show the low battrey cell on screen. Leave the phone and it will automatically switch- on on its own once it has powered up about 2%. It happens all the time with my phone but the above technique always works or fixes it but i think its a manufacture glitch if you ask me.
Regards
Njabulo (South Africa)
+27743461507