DirectX® 9.0b During the Call of Duty setup, the install process will prompt you to install Microsoft® DirectX® on your computer. If you choose "Yes," the Microsoft DirectX setup program will install the appropriate files on your computer. Please refer to the DirectX website for further information or localization updates.  http://www.microsoft.com/directx Q. What is DirectX 9.0b and why do I need it? A. DirectX 9.0b is a set of sound, video, input and network functions developed by Microsoft.  Call of Duty utilizes the functions that are included with DirectX 9.0b. Q. If I don’t install DirectX 9.0b when I install the game, can I install it later? A. Yes. You will need to manually install it. To do so, use the following instructions: 1. Place Disc 1 in the CD-ROM drive.  The Launch screen should appear.  (See AutoPlay if it does not appear.) 2. Click on the "Extras" button. 3. Click on "Install DirectX" and follow the installation process. When DirectX installation finishes, you will need to restart your computer for the new drivers to work. Q. I already have other Windows 98/98SE/2000/ME/XP games installed on my computer. Will the Microsoft DirectX Installer change my DirectX files? A. If you already have other Windows 98/98SE/2000/ME/XP games on your computer, chances are you already have a version of DirectX installed. In this case, the Microsoft installer will detect and overwrite any previous versions with DirectX 9.0b. At that point, you will need to restart your computer for the changes to take effect.  If, however, you already have DirectX 9.0b installed on your computer, the Microsoft DirectX 9.0b installer will detect it and not overwrite any files. You will not need to restart your computer after installation in order to run Call of Duty.