I repair computers so lemme take a stab at this one.
I've seen this before a few times. What I would do is first get ahold of a computer monitor and plug it into the VGA out port on the laptop. Start it up.
If the monitor comes to life and gives you a startup screen or a boot screen or something useful, navigate around whatever you see to get it to boot up. If you get a pic, it might just be a black screen with some lines on it asking if you wanna boot in safe mode yada yada yada.
Point is, you'll know the laptop screen is shot.
If that doesnt work, flip it over, start taking off the access panels. Pop the battery out, remove the RAM, remove the hard drive. Make sure all the little connections are dry and clean. Make sure someone hasnt secretly spilled something on the thing and not told you. Put it all back together, fire it up.
Works? Yippee!
Doesn't work? Shit.
I had a dell do this to me and it ended up being a bad HD. A new one fixed it. It had a flashing key on it too but I dont remember which one.
It's a process of elimination once you re seat the cards and the drive and inspect it for secret spills of unknown origin.
If it normally beeped while it was starting up, and now it doesnt, it could be the HD.... or the CPU... or a power supply failure. A bad power supply circuit will do the same thing a bad PSU will do in a desktop, that being start and just sit there sans post beeps.
You might get lucky and find it's a bad monitor and the desktop monitor plugged into it will get you back in business. Reseating all the plugged in bits might work too.
If you have 2 RAMs in there try removing one. Start it. then swap it for the other in the same slot, try again. keep swapping the ram modules around and restarting and you MIGHT get lucky and find a bad ram slot or a bad ram unit.
A HD you'd have to gamble and buy one to try swapping it, unless you have another laptop that is compatible with that HD model, and see if that HD spins up and boots a different computer.
If all else fails, think of it as a good excuse to go buy yourself a nice new laptop.... with a long long extended warranty.
:thumbleft: