Screen Resolutions do not match, computer does not know where to split the display and will not advance to startup.
You will see a DOS prompt in a black screen. If the dos prompt does not say "Dual Monitor display test is OK!" then the game is in dual monitor failure and will not go forward with game play.
The game is looking for the resolution of each monitor every time the game is powered on, if the computer goes not get a resolution of 1440 x 900 from each monitor and a combined resolution of 2880 x 900 the game will not start.
If this is the issue you have please follow the instructions on the attached PDF. If issue is not resolved with the PDF below the issue is most likely either a bad monitor power supply not supplying properly power for the monitor to start properly or a bad resolution board in the monitor
Replacing the monitor is recommended if resolution board is damaged.
See attached file for more details.