Does your screen have lines running through it ? Is your laptop screen displaying a distorted image read on to find out if this is a problem with your lcd or your laptop motherboard
Follow up:
Many times a laptop screen will suddenly start not working properly and start displaying garbled images or will have lines of dead pixels running down the screen ranging from one pixel wide and in many cases it will be 2 - 5 inches wide. The good news is that sometimes it is not the lcd screen and can be fixed.
The first thing when diagnosing any laptop screen related issues is to connect an external monitor and see if it is displaying normally on the external monitor (Please note that sometimes you will have to press the FN key and one of the f1 , f2 , .... keys to send the picture to the external display). If everything is working properly on the external monitor you have already ruled out any possible graphic card / chip related issues , if it does not work properly on the external monitor either then it is a graphics related issue and in some case can be fixed as well.
So now that you established that the external monitor is displaying properly and your laptop screen is the issue , we will move on to see if it is the screen , a damaged video flex cable or a loose connection.
The next step is to move your screen back and forth slowly to see if at some points you get a normal image that lasts. If when moving the screen you find a position in which the laptop screen functions properly then in most cases it is not the laptop screen that is damaged , rather it may be a loose connection or a faulty cable. If this seems to be the case (that you found a position that the screen displays normally) then you will have to open up the housing of the lcd screen and double check the connections since sometimes over time the lcd cable will start moving out of place. I would recommend reseating all the cables and making sure they are properly plugged in (Please remember to disconnect any power to the laptop before working in the laptop (i.e. battery , AC adapter etc...). Once you reseated everything turn on your laptop and see if the problem is solved. In the event that it is still not displaying properly , inspect the video cable to make sure that it is not ripped any where. In many cases especially if the tape on the lcd cable is brittle it is a sign of a damaged lcd cable either from time or heat and replacing this cable might solve the problem.
Also I have seen cases where the problem was a result of a liquid spill near the socket that the lcd flex cable plugs into , so if you had a spill then double check the area that the lcd cable plugs into to see if there is any corrosion that is causing it to short. If you see corrosion then you can try to clean it off with some distilled water or Isopropyl Alcohol DO NOT USE REGULAR WATER as it will damage the motherboard , let it dry for a few hours and then test your laptop again.
One last thing that may be causing the issue is the switch that shuts your laptop screen off when you close the lid. I have come across cases where the little switch that turns off the display when the lid is closed gets stuck and it results in a dark or dim lcd screen , so try to locate the switch and see if it got jammed.
So to sum it up , if you move the lcd screen up and down and no matter what position your screen is still displaying lines or garbled text but it works fine with an external monitor then it is a 99.9% chance that your screen is faulty and will need to be replaced. If you need help in finding a replacement screen you can visit us at www.nylaptopparts.com