Judging from your reply, there isn't a way to disable Norton as it get so embedded in the system.
I guess that if I cannot uninstall Norton to just "try" Avast!, that means that I can't use Avast!
as long as Norton has to be on the system for me to use in case Avast! doesn't work out.
Thank you for your quick reply and I really appreciate your answer, although I do wish that
I could try Avast! with still having Norton, but having it disabled.
That is correct not whilst you still have NAV installed.
You can uninstall NAV, reboot and try avast, but if you can't do that then installing avast would be pointless. On occasion it may be required that you may have to use the NAV removal tool if thee are any remnants of the NAV uninstall left.
If avast finds any elements of Norton it will usually disable some of its processes to avoid a conflict and if that happened your evaluation experience of avast would be of an AV that isn't functioning fully or possibly not at all.
If you were able to either have a dual boot system or a Virtual Machine set-up then you could possibly test avast, but that (dual boot or AM) in itself isn't the simplest of tasks.