ccsvchst and CPU usage

It seem that this process can soak up CPU in a variety of ways.  My system has a variable-speed fan that really revs up and makes  folks thinks it's about to bust a gut when CPU usage goes up.  Anyhow, I can't relate my problem to any of those already reported [and presumably solved...]

 

I am running Norton 4.3.0.5 (supplied by Comcast) on a Windows XP system with any and all updates Microsoft sends my way.  I use firefox and thunderbird, and I have Norton run scheduled automatic full system scans.  No problems have been reported.

 

My investigations have revealed that ccsvchost runs the user interface for Norton, so I figured it was safe to kill it off, but task manager won't let me (because system is the owner?).

 

Any suggestions would be appreciated.