After Live Update fed me the new patch, I restarted as requested and all was well. But after the first cold boot, the Norton icon failed to appear in my system tray. It wasn't even listed under "current items" in the menu that allows you to customize the taskbar and force specific items to be displayed, only under "past items." When I went to Firefox-->View-->Toolbars, the Norton toolbar was missing. (I also checked under Windows Task Manager processes, but I don't know the name of the program I'm looking for.) In short, there was every indication that NIS had failed to start up.
I restarted the system and this time it did load normally: it was back in the system tray and the toolbar was back as an option in FF. Still, it's unsettling to think this could ever happen. (1) What could explain it? (2) Is there a way to confirm whether the program is running even when there are no indications that it is?
I'm running XP (SP2).