Microsoft released the System Update Readiness Tool to resolve certain conditions that could cause installing updates and other software not to work. You do not have to manually run this tool.
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
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.
You may use Windows Update to download this tool or just download it using following link :-
Windows Vista x86
Windows Vista x64
Windows Server 2008 x86
Windows Server 2008 x64
Windows Server 2008 IA-64
Windows 7 x86
Windows 7 x64
Windows Server 2008 R2 x64
Windows Server 2008 R2 IA-64