If you are having problems with the installation of hotfixes (windows update or the functionality ones, or service pack or a language pack), here are links to install the CheckSUR tool to fix these issues:

System Update Readiness Tool for Windows Server 2008 R2 for Itanium-based Systems (KB947821) [September 2012]
http://www.microsoft.com/en-us/download/details.aspx?id=13833

System Update Readiness Tool for Windows Server 2008 R2 x64 Edition (KB947821) [September 2012]
http://www.microsoft.com/en-us/download/details.aspx?id=14668

System Update Readiness Tool for Windows 7 for x64-based Systems (KB947821) [September 2012]
http://www.microsoft.com/en-us/download/details.aspx?id=20858

System Update Readiness Tool for Windows 7 (KB947821) [September 2012]
http://www.microsoft.com/en-us/download/details.aspx?id=3132

System Update Readiness Tool for Windows Server 2008 for Itanium-based Systems (KB947821) [September 2012]
http://www.microsoft.com/en-us/download/details.aspx?id=3748

System Update Readiness Tool for Windows Server 2008 x64 Edition (KB947821) [September 2012]
http://www.microsoft.com/en-us/download/details.aspx?id=3748

System Update Readiness Tool for Windows Server 2008 (KB947821) [September 2012]
http://www.microsoft.com/en-us/download/details.aspx?id=22931

System Update Readiness Tool for Windows Vista for x64-based systems (KB947821) [September 2012]
http://www.microsoft.com/en-us/download/details.aspx?id=1540

System Update Readiness Tool for Windows Vista (KB947821) [September 2012]
http://www.microsoft.com/en-us/download/details.aspx?id=22931

References:
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What is the System Update Readiness Tool?
http://windows.microsoft.com/is-IS/windows7/What-is-the-System-Update-Readiness-Tool

947821 System Update Readiness Tool fixes Windows Update errors in Windows 7, Windows Vista, Windows Server 2008 R2, and Windows Server 2008
http://support.microsoft.com/?id=947821

958045 Error code when you try to use Windows Update or Microsoft Update to install updates: "0x800B0001"
http://support.microsoft.com/?id=958045