well the software controls the hardware, so it could very well be that. reinstall the drivers, like bill said, and then check to see if you've got a warranty on the puter...might have to replace the screen.
if you move the screen (more open or more closed) during when the screen is getting darker, does it flicker or get better/worse? it could be something with the wiring in the hinge mechanism.
imo, get a pro to look at it...it should still be covered by warranty.
welcome to TechIMO!
~Branson