Thanks for trying out the demonstration version of 3D Railroad Master! This demo requires DirectX 5 or later. For your convenience, DirectX 5 is supplied. If needed, you can install DirectX by using the Windows Explorer and double-clicking the 'dx5eng.exe' file that is placed inside the demo's root directory after installation, then follow the on-screen instructions. If you try to start the demo and DirectX isn't available, you'll see a message indicating this, then the program will exit. After installing the demo, please review the provided ReadMe document for additional information. Again, thank you for trying out the 3D Railroad Master demo. We hope you enjoy it and will be interested in purchasing the full release version of the program. The full version provides dozens of ready-to-play layouts, many additional train cars and scenery objects, allows editing/creating delivery schedules, adding custom cargo, and more. You may contact Abracadata toll free at 1-800-451-4871 or visit our web site at www.abracadata.com for additional information about Abracadata, Ltd. products or to purchase the program.