How to start it in Windowed mode?

[ShotgunSuicide]

I'm trying to start it in windowed mode because when I start the game, I just get a black screen. I assume there's some permissions or whatever else is needed to run the game on Windows 7, but I can't get out of that black fullscreen, so I need it to run in windowed mode first. Is there a config file I can edit to run it in window mode?