You might need to check the version of Microsoft Silverlight installed on your computer. But the latest version of the product is Silverlight 4.
From this it can be said that the update actually is intended for the Microsoft Silverlight version 3. The update KB978464 contains the file “ runtime\Silverlight.3.0.exe”. Microsoft has issued the security update KB978464, dedicated to solve the issues with Microsoft Silverlight. October 8th, 2010 | No Comments | Posted in Windows by bharath