Used to be with Avast thinking of returning

Hi,
I had Avast free since 2008 on my old PC. New one last year came with Norton Internet Security, so for the sake of £15 I registered it. However the year is nearly up so I am thinking about returning to Avast (probably free). However I quite like the idea of the integrated AV, firewall and antispam.

If I were to go for any Avast product how do I go about completely ridding my system of all traces of NIS?

If I were to go for any Avast product how do I go about completely ridding my system of all traces of NIS?
Uninstallers – Security Software https://singularlabs.com/uninstallers/security-software/

General: Uninstalling a third-party antivirus software https://www.avast.com/faq.php?article=AVKB11#artTitle

After running the Norton removal tool I would still perform a search for Norton - Symantec, there are bound to be leftovers even after running the tool and plenty of registry entries if you are confident enough searching in there as well…if not please don’t go anywhere near the registry or it could be a disaster for you.