NIS 2009 runs symantec system framework at 100% cpu

recently, a recurring (daily) problem with nis 2009 -- symantec system framework runs at 100% cpu, my computer freezes and i cannot work for 25-30 minutes at a time. the history screen indicates norton insight submission (what's that?) and pulse updates are running. 

 

i run windows xp home edition with service pack 3, all other scans are run on demand, and the version of nis 2009 is 16.8.0.41

 

this is too long and too invasive to be a "background" process -- what's going on and how can i get back to work??

 

thanks for any help!