Why is my screen all black?
On some systems with particular videocard settings, Allegiance will be completely black when run in fullscreen mode. Switching Allegiance to windowed mode works, but fullscreen is all black.
One user who ran into these symptoms was running an nVidia card using the ForceWare drivers. They solved their problem by turning off the "Antialiasing" and "Antiisotroping" settings in their videocard settings. Turning these off may resolve your problem, too.