OK
This is a very interesting problem you are trying to achieve, for one, I do not know of any method 2 computers can communicate with each other without some form of network device such ast a Network Card, Wireless card, Bluetooth or whatever. Maybe you are a wicked scientist like Doc from Back To The Future and can develop some Quantium Network Technology that gets around this problem of not requiring extra Network devices to get one computer to communicate with that other.
Short of that .... You will need to have 2 Network cards for both machines and a Cross Over Cable to connect both machines up together. After installing TCP/IP protocols and some details and drivers you will now have both computers networked and ready to go. If you are going to do this setup you will need to have ICS (Internet Connection Sharing) for your machine connected to the ISP you dial up on. The other will see this machine as a Server and then the second computer will be a client.
Better option would be say if you have a broadband connection is to make this device a 4Port Modem so you can connect both machines with 2 Straight Through network cables into the device, with of course 2 Network cards in both machines to connect these 2 Straight Through cables into.
Good Luck with your Mission on trying to network 2 computers together without any Network Cables or Network cards, if you figure out a way, let me know ...
DR