Tried to get my resolution the right size and the option scrolled off the monitor.

[Volomon]

Now whenever I start the game up the game is black screen. Where are the config files for this game so I can manually fix this?

[sarmatius]

The file you are looking for is in the WTF folder under the name Config.wtf. There you can add these lines to probably fix your problem:
"
SET gxWindow "1"
SET gxMaximize "1"
"

[Caperfin]

Are you still having this issue?