Connect one of the computer to the Ethernet port on the firewall. If the computer show no IP address when you do ipconfig /all, DHCP isn't enable by default on the firewall so set your computer IP address to something in the same subnet. Use
192.168.1.100
255.255.255.0
192.168.1.254
And then try connecting to 192.168.1.254 with your browser. Use IE.
Make sure you use the guide on how to set the firewall back to factory default.