My girlfriend's iphone 5s screen broke. I bought a new screen on the internet and put it on, but the screen does not work. I ran a test and I put the screen of my iphone 5s and it does not work too. Do you know what that might be? The phone turns on, mame sounds when I charge it, but the screen turns black. I already reset and it remains the same. I appreciate your giving me some help. Thank you very much. PS: both phones have warranty expired.