If you've got a laptop, there's a chance that the screen is defective. If you can, for instance, plug an exterior monitor or projector and get that to work with no issues, that would give you a clue that's the case. You can find replacement LCD replacement panels at Ebay and Google for instructions.
I actually changed one for a cousin (ironically she's legally blind, but she needed the screen for the people helping her see what the images were showing in the screen; for text she had a program to read menus and writing). It's no too hard, but make sure to keep the TINY screws (you need some precision screwdrivers) in a safe place while you do it.
Come to think of it, I ended up with an unbootable Dell netbook after upgrading the BIOS ... It was for a work netbook. The company had to buy an extended warranty for something to come to replace the whole motherboard. Bad Dell!