Hi Ron
Just the one.
I was thinking I might need to put a second in or use a hub or router.
So do you have a separate connection for your Internet cable, or does this also connect to the network card on the desktop?
If the desktop has a separate connection for the Internet cable, then there should be no reason that you cant use the network card on the desktop to connect with the laptop as I described in the first post (in a similar fashion that you described in your home setup).
Remember, that usually you will need a crossover type LAN cable when connecting two PCs together via their network cards (different to the straight through type when connecting to a hub or a switch).
Once they can reach each other via IP address, then you can configure the Laptop to use WinGate as described on the link I gave you.
If the cable modem does use the network card on the desktop, then you can put a second network card in to acommodate the connection to/from the laptop.
Hope that helps