My Iphone won't turn on it just has a black screen I have got it on charge at the moment had it there for about 40mins it has done this once before and came back on from leaving it on charge overnight just wondering why it has done this and if anyone else has had the same problem. Really annoying as it is worth so much. Help 
any ideas i have also try to reset it by holding the on switch and button but nothing happened.
any ideas i have also try to reset it by holding the on switch and button but nothing happened.