Sorry Lisa, but the following is going to be complicated and probably boring.
Unfortunately just uninstalling Norton using the provided routine is not sufficient - it leaves it's sticky fingermarks all over your computer. I don't use it myself, so I can't advise on how to get rid of it - you should be able to find out on www.computing.net.
To be reasonably safe on the internet you really need the following;
1. Antivirus. I hear AVG is fine. I personally use Avira Personal, also free.
2. Lavasoft Adaware.
3. Spybot Search and Destroy
3. Spyware Blaster
4. A Firewall. The one in Windows XP is adequate (though it needs to be switched on), but for Broadband/Cable use I would recommend Zone Alarm.
All the above are available for free download.
They must also be updated regularly in order to protect against the latest threats - weekly is none too often, daily would not be ridiculous.
In fact, I suspect that this is the problem with AVG. If you have not been updating, then it probably expires because they do not want people running obsolete version which will not provide protection, and will give a bad impression of the software.
My apologies if you know all this, but there are an aweful lot of people out there who do not take adequate precautions, and I get a bit preacherish about it.
I was in my local computer repair shop recently when the manager showed me a machine that had bee brought in with over 5000 viruses and other infections; the owner could not be bothered about the protection "because it slowed the machine down". In fact what was slowing it down was that it had been taken over as a slave machine and was sending spam out around the world!
Rant over.