Laptop is on, but nothing show on the screen

Laptop Type: Acer Aspire 3003WLMi, 4 years old.

Back Ground: A few months ago, my laptop's fan started making loud noise. A few weeks ago, it turned off by itself in the middle of my work. I figured it may be over-heated so it turned off. Then yesterday it turned off immediately after Windows XP loading screen show up. I tried a few time, and it still did the same thing. So the next load up, I try to enter BIOS. But as soon as I press [F2], the computer shuted down. The next time I started up laptop again. Nothing is showed on screen, but the laptop is on. and i heard the fan is running and something is reading. I am sure there is nothing wrong with the screen, because i see the back light on screen. and when i hook it up to a external monitor, it shows nothing neither.

Start Up: The hard drive light blink twice, some fan sound, but nothing show.

Please help me with this problem. Any kinds of help are appreciated.

P.S. I opened the laptop and cleaned out the dirt for a few times. I dont think i messed up anything though.