Hey, I searched for a solution on the internet for couple of hours and didn't find a solution. The problem is, that when I launch the game (no matter if singleplayer or multiplayer) it just kinda changes my desktop resolution, then goes back to normal and nothing happens. I tried Windows XP compatibility, running as administrator, nothing helped. It's a legal, Steam version.
Did you figure out a solution... my computer is doing the same exact thing.