Hi Gredrian,
Let me help me you to access all the buttons in Office 2013 applications.
Since this issue occurs with all Office 2013 applications, let us repair Office 2013 following the steps from the link below:
http://support.microsoft.com/kb/2769349
If the issue persists, then let us remove all traces of Office 2013 following the steps from the article below:
http://support.microsoft.com/kb/2739501
Now download and install Office 365/Office 2013 by logging into
www.office.com/myaccount with the registered email address and click Install Office.
Hope the suggestions provided is helpful. If you need further assistance, reply and I will be glad to assist you.
Thank you.