1394 is your firewire card, don't worry about that entry. The WAN item seems like it would be your old direct connection, without the router. You should remove it. OK, I'll run this down, there are two options, either use DHCP from the router or don't.
Step #0) Make sure all firewalls are disabled. Make sure all the PC's have both the Server and Workstation services set to automatic and they are running.
DHCP) You have to have the network card properties set to automatically obtain IP address [this is default]. Nothing needs to be configured, it will be done automagically. Make sure the DHCP Client service is running.
Static IP) Set each PC's IP address manually, using the IP address of the router as the gateway. If it is the default address, assuming 192.168.1.1, then you have to set each PC's IP address and DNS servers. Open the network properties of the card and specify
IP 192.168.1.2, 192.168.1.3, etc. This must be unique for each PC.
Subnet 255.255.255.0
Gateway 192.168.1.1
DNS: your ISPs DNS servers
From here on the directions are the same for both.
Make sure each PC in your network has a unique name, the same workgroup is not necessary, workgroups really dont mean anything. Make sure that NetBIOS over TCP/IP is enabled in the network properties of your NIC.
If you are using XP Home, there is nothing to be done except share something, all security is done through the Guest account.
If you are using XP Pro, disable simple file sharing, then make sure you have identical user accounts with passwords on all the PCs. This is necessary. XP Pro will not allow accounts without passwords to access shares without modifying the local security policy. After that is done, share something.
Do not always rely on the Network Neighborhood, test connectivity by pinging by computer name, i.e.e PC1 and PC2 in network, run from a command prompt ping pc2. If you can do this, but the PC is not showing up in Netplaces, go to run and type in \\PC2, you should be able to access from there.