I had the same problem.
I had to send mine in for a new inverter.
Try tapping the small white button on the top right of your computer.
This will refresh your laptop display and may work for a while.
Otherwise hook up an external monitor and hit the FN and f-4 keys simultaneously, that will send the signal to an external monitor.FYI If you hit the keys again the video signal goes to both , again and the laptop only.
Have you tried to connect it to an external monitor? It has an external video out. If it does, at least the video cards working. Then, as rebel 245 suggested, if you see a dim image, or no image determines whether you need an inverter or an lcd. Also, it's possible that the cable needs to be re-connected to the lcd. Good luck
With the notebook on shine a light onto the screen and see if you can see anything, if you can then its you backlight that has gone out. if you can't see anything. it may be the power inverter
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