Results of SFCfix:
SFCFix version 2.4.5.0 by niemiro.
Start time: 2015-06-30 09:28:37.737
Microsoft Windows 7 Service Pack 1 - amd64
Using .txt script file at C:\Users\user\Desktop\SFCScript.txt []
RegistryScript::
Successfully took ownership and permissions for registry key HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer.
Successfully took ownership and permissions for registry key HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer.
Successfully imported registry key HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer.
Successfully imported registry key HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer\SecureRepairWhitelist.
Successfully restored ownership and permissions for registry key HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer.
Successfully restored ownership and permissions for registry key HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer\SecureRepairWhitelist.
Successfully restored ownership and permissions for registry key HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer.
RegistryScript:: directive completed successfully.
Successfully processed all directives.
SFCFix version 2.4.5.0 by niemiro has completed.
Currently storing 3 datablocks.
Finish time: 2015-06-30 09:28:38.190
----------------------EOF-----------------------
I rebooted the computer and attempted the update again.
The Update FAILED, but with a different error code:
Microsoft .NET Framework 4.5.2 for Windows 7 x64-based Systems (KB2901983)
Installation date: 6/30/2015 9:44 AM
Installation status: Failed
Error details: Code 643
Update type: Recommended
The Microsoft .NET Framework 4.5.2 is a highly compatible, in-place update to the .NET Framework 4, 4.5 and 4.5.1. By using the .NET Framework 4.5.2 together with the C# or Visual Basic programming languages, you can write Windows Store apps. The .NET Framework 4.5.2 delivers better performance, reliability, and security than previous versions. After you install this update, you may have to restart your computer.
More information:
The Microsoft .NET Framework 4.5.2 for Windows and the corresponding language packs are available
Help and Support:
Microsoft Support