Same problem as well. From the event log
Faulting application name: CivilizationV_DX11.exe, version: 1.0.0.20, time stamp: 0x4ca37045
Faulting module name: CivilizationV_DX11.exe, version: 1.0.0.20, time stamp: 0x4ca37045
Exception code: 0xc0000005
Fault offset: 0x001d7905
Faulting process id: 0xcb0
Same happend to me, i just reinstalled steam and civ V and it works now again. I think windows 7 sees it as a spyware thing or something. I got crashes after a windowsupdate i think. but the same 0xc0000005 code i had.