You’re probably correct; however, I got “help” from Microsoft’s forum but their solution (which was really a link to a link to a solution) has so far failed to resolve the issue. It appears that the problem is an error initializing the System.Windows.Media.FontFamily but replacing all of my fonts with working default fonts and all of the associated registry keys with working default registry keys (as was suggested) did not fix the problem, so Im stuck with not being able to install VS2013. Technically no WPF is likely to work but so far I’ve been unable to rectify the issue. I have VS2010 installed but apparently that’s not enough.