Strongly recommended: Get a ROUTER.

Ethernet connections from each computer to the router.

Ethernet connection from the router to the modem.

Start|Settings|Network Connections and create a "simple network" or "home network" on ONE computer. Follow instructions to link the other computers in.

Once your router and simple network is set up, all the computers should be able to use the same router connection separately or all at the same time, and you also will be able to access files (if they're shared) between any of the computers. When you bring a laptop home you plug it into the router, and it's quickly joined to the network to dump/load files from any of the others. To take it back to work, you just unplug the ethernet cable to the router.

For dialup, you can use a modem built into one of the computers and turn on the ICS (Internet Connection Sharing) in the one with the router; and in this case you could probably get by with an "ethernet bridge" rather than a router. Theoretically you can put a second ethernet card in one computer, connect it to the external modem, and share the connection with the other computers via the ICS setup, but it's often difficult to get stable sharing with the simpler ethernet bridge at higher than dialup speeds.

Windws, since Win98, has included ICS and allows you to share a single modem connection with up to 8 computers, but -

Aside from being more stable (and faster) the router should have a "hardware firewall" of at least minimal performance built in.

The router is better.

Actually the router is quite a bit better.

In fact I'd say the router is a whole lot better.

If you were to ask, I'd say that the router is really the only way to go.

The router also should come with all the instructions needed to get it set up. You can likely find a 4-port router for $40 (US) or less, but since home networks tend to "grow" - and you might have guests - I'd recommend getting at least an 8-port. Some newer printers and scanners and such are available with ethernet ports, and it likely will be easier to plug them into a router so that they're automatically shared with all the computers than to plug them directly into one computer, set up sharing, and having to leave that computer turned on so that other computers can use the printer.

My 16-port was around $90 about a year ago, but I was optimistic about my "system growth" allowance. So far I've only used 7 at a time.

John