I have no idea what the problem is, but I've had similar things happen, and reinstalling Windows "fixed" it.

Does your motherboard have built-in video? If so, try disabling it in the BIOS.

I can't imagine that its anything other than software if it works perfectly well in linux.

One last idea. You can remove the device in the device manager. Somewhere I saw something that gave you an option in the device manager to show all devices, including those that had been installed but aren't installed anymore. You can remove any and all video devices, including those hidden ones, then try reinstalling the driver.