Windows 7 high CPU usage with file ccsvchst.exe

Hello

 

Can anyone tell me why file ccsvchst.exe seems to take up to 50% or more of my laptop's CPU time and retain it for an hour or more from time to time?

 

Obviously, this is very annoying.

 

According to the file, I have version 18.5.0.12 which ships with Norton IS 2011.

 

Thanks

 

Martin O'shea.