How does Windows Update (WU) work?
WU provides high priority security and Optional updates for Windows. WU includes AU, a feature that can be easily configured to deliver security and other high priority updates to its users whenever it is most convenient for them. The Microsoft Download Center offers consumers and businesses a wide variety of content that includes downloads available on WU and Microsoft Update and also other updates for games, DirectX, mobile devices, Macintosh and other platforms, server applications, system management tools and developer resources.
