it could be one of four issues. the problem WR2 was inferring to, i believe, is the backlight going out. you should be able to see a VERY faint image of the desktop if its the backlight.
Can you plug a monitor into the laptop to see if the screen is displayed? If you get a display, that will rule out bad graphics chip.
It could be the cable that connects the LCD to the mobo and routes through the hinge came loose or is bad as well.
Or you could just have a defective screen