Magazine CDs are virus checked and will be safe however you do not want to install additional virus checker or firewall as this will conflict with your existing setup.
If you have a year of upgrades with your norton programs then just use this. When your subscription runs out and they ask for a load of money then you can either pay or use free programs like AVG antivirus and Zonealarm firewall both of which are recommended frequently in this forum
Spywareblaster, Microsoft Antispy, Spyboy S&D and Lavasoft Adaware are often available on magazine disks and are excellent programs to have on your system. They are also available to download but if your on dialup it could be easier to install from disc.