An automatic update by steam made Civilization V unplayable on my graphics card. Wat do?

I had recently gotten the Civ V: Gods and Kings expansion for my Civ V game, and spent some time going through the new features. After a week or so, I suddenly was unable to play the game, as it froze in start-up continually. It took me a ridiculously long time to diagnose the problem, and I eventually deduced it when the same thing happened with the new Call of Duty: Black Ops 2 game. So how can I get Civ V to a less-updated point (with or without Gods+Kings)? (and is some solution possible for Black Ops as well?)