Turns on, but before anything happens, it turns off
Basicly, my iPhone turned itself off twice in one week, then the other day, it turned off again, but started itself up again, this time it got as far as loading my pin screen ( so I think ) then it instantly powers down, but then starts up again to do the same again...
When it first did this, it had full charge, and was in a loop of doing this, then the battery died, I thought this might fix it, but as soon as it had charged up, it started it's loop again, whenever it is plugged into anything, it repeats this loop, and I am unable to stop the loop.
What's going on? and how can I fix it?