Originally Posted by Eugene

The easiest thing to be "wrong" and to fix is if this is a simple resolution thing that happens in dosbox with some old games. Try changing the resolution selections in dosbox, starting with original, then the lowest (320 or something similar), 680x400, etc. I think you are running in a higher resolution than will fill the screen, and lowering it should do the trick as long as you have the sim running, just too small.