Some additional thing to try...
Can you try to log on as a different user to see if the result is the same? That could determine if it's a OS user profile issue (vs the normal.mxt that had no effect).
Are you attached to a network or Internet? Can you isolate (unplug from networks ) to see if same happens? That can determine if it's your machine/install or possibly some other external issue.
By any chance, do you have an external drive or thumb drive attached, and/or was one attached when installing? In one of the versions (possibly 10.1) if we had an external attached, part of the install would end up on the external. Never could figure out why (maybe just out network) but uninstalling, detaching the external and reinstalling would resolve that. Worth a look. I could see that slowing things down.