Norton Internet Security 2011 won't work after reboot

I am trying to install Norton Internet security 2011 on a laptop running Windows Vista Home Premium. I can install, update and run, but when I shut down or reboot my computer it no longer works. i have tried uninstalling and reinstalling with no success. I also get a message of cc.SvcHost not found.  The number of days left on my subscription is correct, but I don't want to  have to reinstall and update every time i use the internet.  Does anyone know of a solution to this problem?