I recently tripped accross a better way to monitor what updates need to be applied to a system. This includes all desktop and server versions of Windows based on NT.
Microsoft Baseline Security Analyzer 2.0. Provided by Microsoft and based on the technology in Shavlik's HFNetCheck, is an excellent tool for scanning systems and providing you a list of updates that are required for the Microsoft programs installed on your computer. I say programs, and not the OS because it scans MS Office too.
That all said, I am not 100% sure what versions it will scan, but it definately works on Windows 2000 and up, and at least Office 2003. Anyone who needs to get a view of the updates that are needed, but can't afford the hassle of a full WSUS system, should check the Security Baseline Analyzer.
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