So I recently downloaded Black Ops 2 from Steam. Took me 1 whole day to download all, and after playing some zombies I turn off my Pc. I return home and realize my Black Ops 2 Zombies is gone, I know its only 950mb but what happened? I'm redownloading at the moment, because if this happens to my Black Ops 2 11GB file I'm screwed. Can anyone tell me what happened?