Microsoft Knowledge Base Article 891861 contains the following summary and introduction:
SUMMARYThis article describes Update Rollup 1 for Microsoft Windows 2000 Service Pack 4 (SP4). Update Rollup 1 for Windows 2000 SP4 was released June 28, 2005. This update rollup contains a list of security-related updates produced for Windows 2000 between the release of Windows 2000 SP4 and April 30, 2005. April 30, 2005 is the date when the contents for Update Rollup 1 were locked down for final testing by Microsoft, external beta testing sites, and customer sites. Additionally, this update rollup contains several important non-security updates. This article contains detailed information about this update rollup, answers frequently asked questions about this update rollup, and lists the fixes that are included in this update rollup.
INTRODUCTIONThis article contains information about Update Rollup 1 for Windows 2000 SP4 and answers frequently asked questions about this update rollup. This article also lists the fixes that are included in this update rollup and includes information about security-related changes in the Windows 2000 Telephony Application Programming Interface (TAPI). Update Rollup 1 for Windows 2000 SP4 makes it easier for customers to enhance and maintain the security and stability of their Windows 2000-based computers. For more information about the problems that are fixed in Update Rollup 1 for Windows 2000 SP4, click the following article number to view the article in the Microsoft Knowledge Base:
900345 Problems that are fixed in the Update Rollup 1 for Windows 2000 Service Pack 4 that is dated June 28, 2005.