It sounds like the backlight gave out, but in that case why would a second monitor also show up dark?
My guess is that your graphics card is faulty, perhaps as result of a power surge. It's easy to burn out only one component of a computer with a power surge--it happened to me with a nearby lightning strike that took out my SBC-supplied DSL modem and also the Ethernet card it was attached to. Nothing else in the computer was damaged.
If it wasn't a laptop I'd suggest borrowing a graphics card from a friend to see if it would work. But that wouldn't be feasible in most laptops.
The flashing before the darkness occurred doesn't sound good to me, and is the main reason I think the graphics card is damaged.