Don't use Norton Security at all. Really, there are better, cheaper, safer alternatives. I think somebody sugegsted Zonealarm, which I like, I have also tried Adaware free, Avast and AVG. Overall, I have preferred Avast but I am currently using Zonealarm and once a week doing a scan with Adaware.
It is your computer why let somebody else tell you how to use it?
Dunno if others would agree with me here but if my mum says she has Norton installed I'd say nothing, I know she will come to no harm by doing so. For professional use though - waaaay better choices exist.