I assume you don't want to uninstall??
Can you find a registry setting for it? Maybe that might give you some clues? Do you get the popup every time you start the PC, or at a set time every day or what? If its every time you start the PC, it may be in the start-up bit of the registry, otherwise its probably in the norton section.
When you next see the popup, you could try putting your clock forward a year or so, before hitting the "remind me in one day" button (depends how clever the programmers were being).
Otherwise, you could always spam norton. That might at leat make you feel better.