How to access backed up files

Recently my Bullguard Security was replaced by Norton Security. I noticed that Norton was telling me that my Libre Office program was in need of an update. So I clicked on 'Update' and my Libre Office was updated  to Libre Office 7.3 from Libre Office 6. something (sorry, can't remember the older version).

Now I can't access any of my documents in Libre Office and Libre Office won't even start up.

Basically the update has somehow blocked Libre Office from even starting up.