I've finally given up on Norton Antivirus and Internet Security 2006. It's been removed from the laptop, wiped the desktop. We're now using Avast Home Edition, which incidentally is FREE. The Professional version costs money, and might even be worth the upgrade.
Norton was creating too many problems. Recently, Windows would not shut down properly on EITHER system, and the laptop was running SLOW. Suspicious timing, since Windows OneCare just came out. Alas, I cannot blame Microsoft. I've had problems with Symantec products before, so I was not surprised.
I have tried McAfee before, and also have CA eTrust Security Suite. Neither of those are worthy.
Avast just seems to work. It works great on Windows XP, as well as the beta of Windows Vista. It's nice when something just works.
I was about to lose all faith in computers, specifically Windows computers. I've regained it...for the moment. I have my credit card poised to purchase a MacBook if anything else goes awry. I'm about out of patience.