Original post by: iPhone 3GS KING ,
Make sure the cables are not torn or ripped, they can rip pretty easily. If they are damaged purchase a new screen, they're relatively cheep. If they're not damage take the cables out and put them back in again. There is a white line on the cables [image|1387354] make sure the white line is parallel to the plastic screen connector. Also make sure the latch on the screen connector is closed.