No, the product key isn't on the CD. You can use one CD with any number of valid product keys for that software.
Norton System Works is, in my experience, the cause of a lot of problems. I agree with Styxx...use only the anti-virus and firewall, although I've found that one of the free firewalls...Zone Alarm and Sygate's Personal Firewall are the two I've used and can recommend...to be much less problematical and do a better job than Norton's firewall.