symantec actually recognizes how pervasive their application is, and puts a tool out on their site called symnrt.exe. You need to first go to the add/remove applet, remove everything norton/symantec related, then run that to clean all the other traces up. Once you've run that, install the AV of your choice.

Says something when the maker has to put a tool out like that. Specifically, it says 'we made a big application that really doesn't want to come off your computer'.

It's also not a bad idea to do a manual search of the registry... looking for Norton/Symantec folders-- just right-click and delete... this can remove the last vestiges of Norton --then REBOOT before installing AVG. You can also use the windows search tool-- with a few options like "check hidden files/folders" looking for:
Norton
Symantec
NIS

of course... BE CAREFUL about what you delete --if you are not comfortable with this ...don't do it. I do it with things like Norton-- because 3 months down the road, I'll have a crash of program I've used a million times-- look up in the logs-- and it's a tiny bit of NAV left in some dark corner causing the issue. One of the most pervasive programs EVER IMHO.

marking as answered.