Excel 2013 stopped working -- seems to crash on launch - Windows 8.1

view full story

http://superuser.com – New Toshiba laptop with Windows 8.1 - came with Office 2013 installed. I had Excel working and edited a few spreadsheets as a test. Then I set up another user account as Standard and ran some Windows Updates. Now Excel will not launch. I've not been able to see it in the process window, however when I pin the shortcut to the task bar I see it highlight for about 4-5 seconds indicating that it is trying to start but then closes. Word and Powerpoint do the same thing! How can I troubleshoot this? I'm Windows experienced but 8.1 is new to me. (HowTos)