Same problem here i dropped mine at first it showed slight colors in a dim light look then i took it apart pushed all ribbons back in place after removing them and now no response at all not even a tiny bit of light i have a new screen for it and cleaned the old adhesive off gently as possible so i know for sure it aint damage the LCD but this particular thing has happened with my last iphone its very irritating but im sure that it must be something that isnt intact as it was when it was factory put together please help preferably an apple tech rep or someone whose very knowledgable of these type of situations