Can you give me more details on what happens? The computer doesn't come on at all? Or it does, but the F2 and F12 keys don't work? If the keys don't work and the computer comes on, what happens?
It's obvious he means you press the power button, it boots up, but does not load windows. You just get a total black screen with a blinking _ at the top left screen. Could be many probs, I suggest trying to see if any loose cables from the hard drive to the mobo.
Edit: I read in a google search some ones power supply was just worn down with age, and couldn't give enough power to the GPU. Maybe your battery is failing? Try keeping it plugged in and see if that helps.
Double Edit: I also know nothing about lap tops to help you further.