My network is fixed wiring and not wireless, initially had some problems, but the secret is to let windows do it and you nominate the addresses for each card and it should work ok.
EG for my main computer I am using:

IP: 192.168.1.51
Subnet mask: 255.255.255.0
Default gateway: nominated IP address
Pref DNS: nominated IP address

Next computer:

IP:192.168.1.52

Remainder as for the main computer

does this help at all?