Blank laptop display

My wife was recently using our older Dell 8500 laptop and she said pink lines appeared across the screen. She didn't know what they were so she closed the laptop to put it into sleep mode. I took a look at it when I got home, but found the screen blank when I opened it. I tried turning it off and back on, but it always does the same thing: the screen starts out blank, then a white gradient moves from left to right across the screen followed by a black gradient that moves from left to right, leaving the screen black in the end.

I figured my LCD must have going bad, so I tried plugging it into an external monitor using both VGA and svideo. However, the monitor never comes out of power-save mode, as if it's not receiving any signal from the laptop. Does this perhaps mean I have a motherboard or video card problem?

Thanks for the help!