The best way to do it is to buy a small network kit..
These are around £35 ($50 ??)..
You get a couple of NICs, an 8/10 port hub and some cables..
It's really easy to set up in windows, just give each machine a different IP address, make the one with the modem the default router for the others.
Then install SETIQ on the one with the modem.
When you need some actual help, post here and I'm sure we'll be able to sort you out...
cheers,
Col.