Chosen Solution
I dropped my phone on the stairs and it dented the area near the volume button. At first, i clicked the power button and the screen would light up a bit but nothing would show up. And then eventually it went to grey and white lines and just turned off. I tried holding the power and home button down for 30 seconds and it did not work. Also the screen popped off a little bit but is still secured to the device.
Try another screen, the screen already got damaged from the cables being pulled as the top part has pushed up. Try holding home + power button for 10 seconds then try plugging into a computer with iTunes open to see if the phone still detects. If it still detects then it’s the screen.
