I'm having a similar issue here as well. Everything should be good to go. Drivers, paths... etc but i get this grey screen, then nothing. When i drop the resolution, the game will actually launch, but it's all black with just a tiiiiny square of the menu in the top left while the music plays on in the background.. teasing me. Can't seem to figure out what the heck the issue is.
Weird. The problem seems to have sorted itself out... I can run the game, just not on the highest res or it'll crash before it starts. And alt tabbing, lets just forget about that. BUT IT WORKS!!!! Huzzaah!