Do you need both hardware and software firewalls?

I am using a broadband router which has a firewall built in. Is it still necessary to run a software firewall? Steve Gorwits

Yes. The firewall in the router should stop most probes, but if your PC gets a virus or Trojan from a USB drive, a program you have downloaded or some other source, the router will not stop it from calling out. And after it calls out, your router firewall will not block the response. You need a software firewall to control the programs running on your PC: not only malware but also legitimate programs that access the net without telling you.