Very recently, I let my laptop (HP) battery get too low, and it died on me. Usually, upon plugging in the adaptor, everything starts right back up again. However, this time, the laptop runs, but all I can see is a black screen. I can even hear the little chime when windows starts (vista), but all I can see is black. I don't think it's a backlight issue, as I the black screen still emits a sort of "glow". I know I need a new battery, but as long as it's plugged into the power supply, shouldn't it work fine? I've already tried the electro static discharge several times (unplugging power and batter, then holding power button for 60 seconds) as was suggested by most forums that I read. This didn't work at all. I'm just wondering what it could possibly be, and if there were any easy fixes to this before I took my computer into a professional?

Try to connect it to an external monitor - If you get a picture on the monitor you know that the computer works and the graphic card works. If there are no picture on the monitor, it could be the graphic card which is "burned"..
There could be other explanations, but first you must tell us the maker and model. - Who knows, somebody might know of a problem just like it with this or that model.. Or maybe there are a keyboard shortcut which turns of the screen, to save battery..

CONNECT TO EXTERNAL MONITOR AND ENSURE IT DISPLAY, THEN CHANGE THE DISPLAY CABLE

I ALSO HAVING SAME PROBLEM....I CONNECT IT TO EXTERNAL MONITOR .. ITS SHOWS NORMALLY...

I have a dell Inspiron 1501 it's doing the same I can only see a little but it's mainly black and I tried adjusting the brightness but it won't do a thing