I think I messed around with the resolution in dod to one that my computer couldn't handle and now I can't change it back so nothing appears on screen.... is there a safe mode or something... i'm so stupid...
I'm guessing the cmd line option '-w <#>' which supposedly 'sets video mode (# is the number of pixels wide)' is what you want.
Try adding "-w 640" (w\o quotes) to your cmd line arguments if that is the right setting.