NIS runs even when Silent Mode is turned on

I posted a thread a day or so ago about a problem with NIS running when I was running a full screen app (game). Since then, I've gotten some new info which makes me think it is a bigger problem.

 

I turned on "Silent Mode" from the NIS tray icon and watched a CPU monitor for an hour. Every few minutes, roughly every 5 minutes, NIS would spike my CPU for around a minute. So, NIS is running regardless of the setting of "Silent Mode". I'm beginning to wonder if  something like Live Update runs regardless of the setting of Silent Mode or the running of a full screen app?

 

Below is a screenshot of the NIS performance tab during this time. It shows the NIS spikes. The graph shows ~50% CPU utilization during the spikes. That's because I'm running a single P4 with Hyperthreading, so the system thinks it has 2 CPUs.

 

Performance 1A.PNG

 

 

Could someone from Norton tell us what NIS is doing/running even when "Silent mode" is on and how to stop it?