I am not a MS Office guru but these are some MS Office 2013 issues I faced, and some solutions that fixed mine; might fix yours, but no guarantee ok :p
These are some shortcuts that nice to know in MS Excel 2013. Some are really helpful as previously when I wanted to Save as, I would press Alt + F + A. However in 2013, I need to press Alt + F + A + C (for Computer); So it's really nice to know that Alt + F2 or F12 is save as.