Accessing old back up files after reinstalling the app

Was told there was a fault in my norton installation and that I would be taken through the process of deleting the app and installing a new version.   In that process another fault appeared and I perforce eventually had to install the app manually.   I now find that I cannot access my old back-ups from my indows 10 laptop although I can still get them on my phone.  How do I resurrect them on my lap top ?