I have a solid love/hate relationship with Norton. It's top-heavy and awkward, but it is also relatively easy to walk new users through, and to support. A system admin can also set it to be (almost) idiot proof. Norton is very effective, and well worth the $30 you can expect to pay for an upgrade.
There is one more compelling reason I would recommend that you renew your subscription: Norton spiders deep into the registry and assumes command of XP unlike any other software I've ever seen. Completely removing it is almost impossible, and "uninstalls" often don't go well because registry keys the replacement software wants to use are not recognized properly after Norton. The only 100% effective way I know to clear Symantec out of a system is a full format and reinstallation of XP.
In short, you are asking for trouble messing with a Norton install.
If you already know about the difference between a "firewall" and an "anti-virus" program, skip this next part.
Anti-virus protection, which you have, scans files like email attachments. A firewall protects your computer from unauthorized Internet activity. XP has a built in firewall enabled by default, but it's not as good as third-party ones that are allowed to update whenever the computer is online. If your firewall is off, your modem should be unplugged, and you should not be online. (Online means connected to the Internet, for example, reading email or surfing.) You need a good firewall because AV (antivirus) software is not enough. Trojans and worms come through the Internet connection (Yes, dial up, too) and are constantly scanning for unprotected computers. They either steal bandwidth, or resources, and/or begin sending mail rapidly to every address they can find on your hard drive to either infect other computers, or launch denial-of-service attacks, turning your computer into a “zombie”.
Spyware and Adware are different. They will change your home page, stall your system, send out personal data to target ads to you, based on your surfing habits. You get them by accident, or hidden in other programs or dowloads that you think you want. (There is no software program out there that is worth the extra ads and spyware. There are always clean and free alternatives.)
One of the malware techs has a line as his signature that sums up Internet Security very well. "Security is a process, not a procedure."
If you are still awake, I hope you found some of this info useful.