1. Video cable disconnected from the LCD screen.
2. Damaged LCD screen.
Possible troubleshooting steps and repair solution:
1. Check the connection between the video cable and LCD screen. It’s possible that the video cable got disconnected when the laptop was dropped. Try reconnecting the video cable first. Make sure the video cable is seated all the way down into the connector on the back of the LCD screen.
2. If reconnecting the cable doesn’t help, most likely you damaged the LCD screen. The screen has to be replaced.