Laptop screen works in BIOS, but not in Windows

[XistenZ]

I have a laptop where the display works perfectly up until Windows has loaded (it still works when Windows is being loaded, you can see the logo etc). When it gets to the desktop the display behaves really weird, it's like a trail of light is moving from the upper right corner of the screen downwards to the left side of the screen to finally turn black. It's hard to explain, but the screen doesn't go straight to black/nothing but flashes and then dims out in the manner I just described.

The brightness keys on the laptop are working, I can see the brightness (darkness?) change as I use them. External monitor works fine as well.

First I thought it was probably a driver-issue, but neither updated drivers or even a factory reset fixes it.

What causes a display to behave like this, only in Windows? It's really weird.

 

[rgd1101]

Sound like GPU fail. Windows run higher resolution then bios screen.

 

[XistenZ]

But the GPU renders perfectly fine to an external monitor...

 

[XistenZ]

I deactivated the ATI gpu so the laptop uses the processor (Intel HD Graphics). So yeah, guess you were right about the GPU failing

Now the problem is to make sure the laptop stops reactivating ATI...