ShawnaR and I share the same network, and I also use a Mac. There are so few viruses built for Mac that a firewall is all that's needed. I am so thankful for this. I used to work in IT, I know firsthand how much an anti-virus can mess with your computer. But windows users really have no choice but to run an anti-virus program. Yup, I can't see me ever going back to a Windows computer for everyday use.