Bug 1.0 Disappearing text, then black screen

Game starts up fine, then a few minutes in all text disappears. If I then alt-tab out of the game and try to return, the screen is black. This bug just started happening today; it never appeared once in the 3-4 hours I played previously, and I haven't installed any other programs or made any other changes of which I'm aware.

Have uninstalled/reinstalled (including deleting files in "My Games"), updated video card drivers, etc. to no avail. Game is currently unplayable.