Ok, If I have understood...
1 plug the cable.
2 Have you put IP addresses on the two computers?
If it's not the case, go in the network properties --> TCP/IP and put IP adress for example 192.168.1.2 (netmask 255.255.255.0) for the first and 192.168.1.3 netmask 255.255.255.0 for the second.
When it's done, launch a DOS command prompt and type "ping 192.168.1.2" on the PC with the IP address 192.168.1.3.
Do the same thing on the other PC (change the IP address in the command)
If you have replies, there is the hardware connectivity.
If it is not the case, there is maybe a problem with the cable or with the LAN card.
Be sure that the Two PC are in the same "Workgroup", Go in the system properties --> Computer name.
Now you should be able to see the other PC in the network neighborhood.
You can also try to find the PC by looking for the IP address .
Regards
GD