Having two resident scanners installed is not recommended as rather than provide twice the protection it can cause conflicts that could leave you more vulnerable.
Norton is probably the worst at co-existing with any other AV.
NAV can be a pig to get rid of. First use the add remove programs to uninstall and reboot.
Then install avast and reboot.
If NAV proves difficult to remove:
This link, which is for a program removal tool that can remove the remnants of a number of different Norton Programs: Removing your Norton program using SymNRT, just checked and it only goes as far back as the 2003 version
For sure not, each finger to a group of keys in the keyboard, the same finger to the same group all the time 8)
It’s easy, but you need to learn and train.