|Do you know for sure that it is still booting even though you can't see the screen? A lot of times, if the laptops memory goes bad, when you press the power button, the lights will turn on, but the computer will just sit there and run with a black screen (however, in rare occasions, the onboard graphics card can go out.) If you have some similar ram laying around, try switching it out. Most of the time, that will fix that problem. If it doesn't, you may have bigger problems.|
I guess you could also try connecting an external monitor to see if that gets any video. (You may have to use the function-F8 or whatever your keyboard says to make the video go to the VGA port.) If you don't get video on the monitor, I think it would be safe to assume that it is your memory.