Hi Again. As luck would have it, VS 2012 displayed the following error message:

Access to the path'C:\Program Files (X86)\COMMON FILES\MICROSOFT\EXTENSIONMANAGER\EXTENSIONS\Microsoft\Windows Kits\8.0\Desktop SDK' is denied.

Ownership had not been assigned. When I assigned ownereship to the administrators group, of which I am a member, VS performance improved 500%.

I hope this information helps someone else.