My girlfriend threw her iphone 4 onto the floor and cracked her screen and back plate. i replaced both the screen and back but when I turned on the phone the screen is white. I don't hear any noises when pressing the screen but does show up as a device on the PC and does vibrate when pluging it in, I have restored the device but result is the same. I've also done some suggestions i've read on the forums here with no success. It has a warranty but because i replaced the screen thats done. and last time i tried to bring a phone with a cracked screen to the apple store they wanted $230 to replace the phone. Any suggestions on what I can try would be greatly appreciated.