OK...This is the resolution...it took a while, but on balance, the outcome is satisfactory.
Two customer service reps and a couple of hours of painful (for the CS reps, that is) discussion later, we have resolution.
My problem was that Symantec had auto-renewed me for another year of NAV and that was never my intention. They'd charged an old (no longer valid) credit card account that had been closed last year. I'd actually already purchased a new copy of Internet Security for all 3 of my computers, and no longer needed to run NAV.
I could not figure out how the auto renewal actually allowed them to charge my account.
I found out that Symantec had done what is called in the credit card industry as a "force post." That means they override the authorization process and just send in the charge to the credit card issuer without having been authorized.
I asked for a credit because I did not intentionally authorize automatic renewal and actually had already purchased replacement software on my own. I knew that force posts are frowned upon in the credit card industry. They virtually guarantee the cardholder wins if the charge is disputed.
But I did not want to have an adversarial confrontation with Symantec (because I like their products) and decided to work with them. That is when I tried Nate, the robot CS representative and could not get an answer. That is also why I posted here.
So long story short, the gal at Symantec, walked me through the install of Internet Security, deleted NAV from my computer, and got me registered as an IS subscriber for 2 years (thus avoiding giving me a credit for the renewal of NAV that was not wanted). I would have preferred a credit, but the 2 year (plus an extra month for the hassle) was good enough.
Now...With a little luck Internet Security will not cause the loops (and subsequent 100% CPU use) that NAV used to cause. Norton AV has always worked well for blocking viruses and identifying stuff like tracking cookies, but it had that one defect, that was maddening if you walked away from the computer for a few minutes and the software decided to launch an "idle time" scan.
A perfect solution? No...but close. Thanks for the link, Dick.