The phone shut down as it ran out of battery, I tried holding down the power button down about 20 times before the lock screen turned on. It lasted about half a second but I managed to see that my battery was on 6%. It's definitely not flat... Every time I hold down the power button it shows the Samsung logo then turns off or loads to the lock screen then turns off. I have no idea why.. I have also tried tapping the back of the device as it turns on and that seems to work a bit... Please Help?!?!?!