My screen only works at certain angles

Do you see a faint image on the screen when the display is out? You might want to use a flashlight from behind the screen, and see if you can see anything on the screen when the display is dark. If you can, this most likely means the inverter cable is being crimped and needs to be replaced or at least re-positioned. If you can't, and there is absolutely nothing on the screen when it's dark, then it's likely the display cable and I'd follow Mayer's instructions. Also, make sure the cable is firmly seated on both ends...sometimes it will simply be loose, and the motion of closing the case causes it to disconnect. But more often than not in your situation, it's the inverter cable, and you'll see a faint image on the screen.