My iphone 5s suddenly doesnt work. When I charge it, the apple logo flashes for a second then turns off then leaves the backlight open. When i remove it from the charger, its just black screen. I tried pushing the power button and the home button at the same time for many times but it doesn't work. I also tried plugging it into my itunes but my laptop cant see or read it. Please help i really need to use it!!