Networking XP Home

I have two computers running XP pro that I am trying to network. One is a Dell Dimension 2400 and a Dimension 4400. I have a Linksys BEFSX41 high speed router/firewall acting as my DNS server. The problem is the two computers can get to the internet, they are in the same IP range, but they cannot see each other. I cannot ping either of the computers IP’s. I also tried running the windows network wizzard on both computers, but it didn’t seem to work. I have disabled windows firewall on both computers. Both are running Norton Internet Security.