Getting a black laptop screen

I get a black screen when I boot my laptop.

The laptop was in sleep mode initially, so when I pressed the power button, it looked as if it woke up from sleep mode, but the screen was blank. So, I held down the power button to force shutdown the laptop and then removed the battery. But after booting the laptop the screen still remains black. The bios/boot screen remains black as well.

I have tried connecting it to external hdmi/vga/s-video devices and booting still no go.

Windows loads fine, as I can type the password and get the 'Ding', then alt-f4 and shutdown windows.

If it helps, the laptop model is Asus G1S-A1.

Thanks in advance!

Update:

After several hours of searching for a solution, I have decided to give up on this. The best option is to replace the motherboard, since the GPU is soldered on the MB. I would have happily replaced the MB, but couldn't find a replacement anywhere online.

So, I will have to buy a new laptop (!asus) pretty soon and transfer the data+code.

Thanks for your response.

Update2

I got it to work!!!
Opened the laptop and used a hot air gun @200F and heated the GPU for about 1 minute.
Then used a cloth to pressed the chip and held it for sometime. Applied back thermal paste, put back heat sink etc. and voilà! I think, I just got lucky.

^{Disclaimer: I disclaim any liability for any damages that may result from performing above steps.}