Ever hear of this tool before? It looks like a very handy utility to check on the status of your system. According to the Microsoft Support Knowledge Base Article, KB947821, you should never need to download the tool. Apparently your system would be able to indicate that it is experiencing a problem that this tool can remedy and prompt the download via Windows Update.
However, Microsoft knows the geek in most of us and provides a download from the Microsoft Download Center that will let us run the tool just to see that everything is actually OK.
What is the System Update Readiness Tool?
System resources, such as file data, registry data, and even in-memory data, can develop inconsistencies during the lifetime of the operating system. These inconsistencies might be caused by various hardware failures or might be caused by software issues. In some cases, these inconsistencies can affect the Windows servicing store, and they can cause software updates not to work. The System Update Readiness Tool tries to resolve these inconsistencies.
After you download the System Update Readiness Tool, it runs a onetime scan for inconsistencies that might prevent future servicing operations. This scan typically takes less than 15 minutes to run. However, the tool might take significantly longer on some computers. The Windows Update progress bar is not updated during the scan, and progress seems to stop at 60% complete for some time. This behavior is expected. The scan is still running and you should not cancel the update.
So if your like me and want to run this tool right away then head over to http://support.microsoft.com/kb/947821 and read the rest of the article which has links to the download for your system.