Sorry to hear that! I heard the same thing from a different Steam user recently, and I think I might have figured it out...
I've updated the redistributables that Steam should install for the game. I'm not sure whether you would need to reinstall it or not. If it's not too much trouble, please could you try these things?
1) Restart Steam completely and try running the game again.
2) Try the "Verify Integrity of Game Files" on Steam (in the Properties menu for the game) and then try running it again.
3) If that doesn't work and you'd like to try one more thing, it wouldn't hurt to uninstall and reinstall it, assume that's no trouble.
I'm hoping (1) will do the trick. Let me know how it goes (I can a couple more ideas too).