Help for a computer retard

[Spiderbot01]

I want to play battle for middle earth against my brother.

We have two PC's, two games and an ethernet cable.

Because of the archaic settings on the game, people seem to say the only way to play is to turn off the internet. But alas, as the other computers in the house require the router this is unfeasible.

How do I set up a network just between the two computers using creating a LAN? One machine is Windows 7 and one is XP.

Any suggestions?