Grey screen of death

Hello,

I was messing around in the video settings in demigod, and as soon as I set AA to 16* Q the screen went grey, just one solid colour. I waited a couple minutes because I figured it would revert if I didn't hit an accept button, but that didn't happen. I've tried reinstalling but that didn't help. Does anyone know how to reset the graphics settings from somewhere other than the in-game menu?

Thanks