Laptop wont boot up

[foxtrot129]

I'm at a dead end. My asus g750 laptop wont boot up. I turn on the power and the power led turns on as well as the power led on the front of the laptop and I can hear the hdd spin up but the screen is black. I've hooked it up to another monitor and that didn't work so I dont believe its the screen. I've already taken it apart cleaned it out, looked for any signs of damage and there is nothing. The numlock light is on on the front of the laptop if that means anything as well as the power LED. The light for the hdd turns on when I try to boot it but then turns off. Prior to me taking it apart the power led wouldnt even turn on and the hdd wouldnt spin up. It's not the power source or the battery as I have already tested them. Any help would be greatly appreciated.

 

[webworkings]

If you hooked up another monitor and get nothing on it either, it is completely possible that your GPU is toast.