| Sounds like either a loose connection, or the circuitry just going bad...
Laoptop LCD's are usually pretty expensive. If you're comfortable taking it apart, I would look for any loose wires around the screen. There will also probably be a board either toward the bottom, or off to one side, which is about 4 or 5 inches long, and kinda skinny, called an inverter board. Look for any black or brown spots on it. These boards transform the low voltage power from your battery or AC cord into high voltage power needed to keep the screen lit up, and they're usually one of the first things to go. Usually the symptoms of a bad inverter board are very dark screen, or screens without any image at all...so I don't know if that would be the problem in this case, but its still worth checking out if you're having problems. | 
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