Game won't start

[Cao Cao Mengde]

I got the auto update downloaded, and now it just hangs at 100%, and wont' start, saying there's a Disk IO error. I know that there isn't a problem with my hard drive, as all my other games work. I have over 50 GB of space on my hard drive. I've already reinstalled Civ 5 TWICE, as well as Steam, and ALL of my games, and it still doesn't work.

What the hell?