Civ 5 worked just fine since it came out (i installed it then).
It started crashing yesterday. It will run on Direct X 9 (windowed) and it lags allot with pixels rendering incorrectly.
In Direct X 11 mode, it crashes as soon as the 2K logo comes up.
I have the latest nVidia drivers, as well as the latest Direct X version.
I've tried disabling the start-up video in settings.
I uninstalled the game, deleted any residual files and re-downloaded it from Steam.
still no luck.
I searched allot of forums, and still couldn't find any solutions (most posts were from 2010).
might be steam problem with detecting the game and lead to crash or lags, or other third party tool that detects D3D applications (fraps, msi afterburner, xfire).
post your problem to steam support they might help you with it.