Updated:
Microsoft updated DirectX 9.0a End-User Runtime on March 28th.

Microsoft DirectX is a group of technologies designed to make Windows-based computers an ideal platform for running and displaying applications rich in multimedia elements such as full-color graphics, video, 3D animation, and rich audio. DirectX 9.0a includes security and performance updates to graphics and networking components. This release also resolves a connectivity issue using some network routers.

Expected download sizes are now less than 8Mb for the end-user runtime on Windows XP and less than 9Mb for Windows 98 and Windows Me.

NOTES:
  • DirectX 9.0a End-User Runtime setup requires an internet connection during setup. The DirectX 9.0 Redist is available for download for those users that do not have an internet connection available during installation or when setup has trouble connecting to the Microsoft server.
  • The DirectX 9.0a runtime cannot be uninstalled. We recommend Windows Me and Windows XP users create a "System Restore" point before installing. For information on creating a restore point, please refer to the following Microsoft Knowledge Base articles:

    Windows Millennium Edition: Microsoft Knowledge Base article 267951.
    Windows XP: Microsoft Knowledge Base article 310405.