Some other things to try (depending on how tech-comfortable you are):
Unplug all USB devices and peripherals that aren't absolutely necessary to running the game (and if absolutely necessary ones use special driver software, consider switching those out too). This sounds odd, but sometimes these things' drivers can interact oddly with video. If you normally use dual monitors, don't just switch to single monitor mode in display settings - unplug the unused one. Reboot after unplugging everything.
Disable Steam interface components and try it in other modes. (Turn off overlay/community stuff, try offline vs online mode, etc.) There might be some interference there.
If you can get it to launch at all that way, try running the game with Windows started up in Safe Mode. (If it displays things in safe mode but not when running normally then it's highly likely that there's a driver - not necessarily a video driver - mucking things up somewhere.)
Try both newer and older versions of your video drivers, since specific builds are sometimes glitchy, especially with new/in-development games.
Install/reinstall DirectX (check the Microsoft site for an appropriate version). It might also be worth checking seeing whether there's a driver update for your motherboard.
