Microsoft Patch Registration Cleanup Tool

Brief Description:
On a computer that has a Windows Installer based product installed, you may receive an error while installing an update for the product and the installation of the update may fail

Windows Installer uses the registry to record information about updates installed for each Windows Installer-based product. These registry keys help identify the state of each update: registered, applied, superseded, or obsoleted. Information about installed updates is stored across several registry keys and values. To allow for the product to be in a serviceable state in which it can be repaired, updated, or uninstalled, it is critical for the data in these registry keys to be synchronized. When the data in these registry keys is no longer synchronized, maintenance mode operations cannot be performed on the product .msi file.

The Patch Registration Cleanup Tool helps resolve some issues that are related to invalid or corrupted update registration. This tool lets you bring the product back to a known state so that you can reinstall updates.

http://support.microsoft.com/?kbid=976220

direct download for the Patch Registration Cleanup Tool

Applies to all currently supported windows versions from XP SP2 up to Windows 7 including all versions of Vista ( SP1 and higher) & server 2003 (SP2 ) and server 2008