You need to be using a static IP setup.
set computer #1 IP to 10.0.0.100
set the netmask to 255.255.255.0
gateway to 10.0.0.1
and leave the rest
set computer #2 IP to 10.0.0.101
set the netmask to 255.255.255.0
gateway to 10.0.0.1
and leave the rest
plug in cable and eh voila oh and make sure you File and Printer sharing setup.