The firewall in the router only protects inbound connections. The outbound protection is WELL DISCUSSED so I'll keep it to the shortest of possible replies here.
As the family geek, I'm more or less responsible for the well being of the computers for most of my family. My grandparents have an old PIII, which works quite well for them. Simple web browsing, e-mail, etc.
Currently, their machine has a hardware firewall (built into the DSL modem) and a software firewall (ZoneAlarm). Do they need both? Is just the hardware firewall enough?
This is an old machine so saving a few cycles would be great, but not at the expense of security.
PIII @ 500 MHz
256 MB RAM
Windows 2000 (SP 4)