It could be a problem either with the graphics chip on the motherboard or the LCD panel. You can try below mentioned steps and isolate the faulty part:
1. Try connecting an external monitor to the laptop and check if you can get regular video. If you get video on external monitor follow step 2 and 3 else follow step 4.
2. If you get normal video after connecting an external monitor to the Laptop, it indicates there is some problem with the LCD or any of its components. Take a technician's help and reseat the LCD cables once. You can check below mentioned link to see the steps on how to reseat the LCD cable:
3. If after reseating the LCD cables the issue is not fixed it indicates the issue is with the LCD panel or the cable. Replace first the cable if the issue is not fixed replace the entire LCD panel.
4. If you do not get video on an external monitor in step 1, it indicates the graphics chip on the motherboard is not functional and would require you to replace the entire motherboard.
Before you proceed for any replacement please go through the following link to check your computer's warranty status:
If the computer is still in warranty, please send the computer's System Service Tag Number in a direct message. I have added you as a friend. Please accept my friend request. I am sending you a private message as well. Respond to the message and provide system's Service Tag and contact details so I may access your system records and check for further course of action(do not post the System Service Tag Number on any open forum).
Please do write back to us.