Vista updates fail everytime I run update

Whenever I run windows update or try to install anything windows related such as .net or microsoft webcam software, I always get an error in the setup which causes the installing to crash or fail.

Below is the .NET crash report

Update to .NET Framework 3.5 Service Pack 1 for the .NET Framework Assistant 1.0 x64 (KB963707)

Installation date: ‎8/‎26/‎2009 1:33 AM

Installation status: Failed

Error details: Code 8007064C

Update type: Important

The update to .NET Framework 3.5 Service Pack 1 for the .NET Framework Assistant 1.0 for Firefox addresses several compatibility issues with version 1.0 of the extension.

Try install this update from Microsoft Download Center if it also fail you have to completely remove NET Framework 3.5 by using tools NET Framework Cleanup tool Aaron Stebner's WebLog : .NET Framework Cleanup Tool User's Guide
and install NET Framework 3.5 again and hotfixes