I use Win7 pro. Each and every time i launch ANY Mortal Kombat title i recently bought, dosbox has sound, but NOTHING for visual, only a big green wallpaper and a black mouse pointer.

I had something similar... but I fixed it by opening the .conf file of the game and trying out some different renderers.

It's the "output=" line in the .conf file. The comment section above it lists all possible values for it.