ok, the only way that setup will work like that is if your ISP gives you multiple IP addresses which usually does not happen w/o you paying for more. Here's what you need to do and exactly what I have currently working:
First of all, you don't need to use the switch, but you can, either way it will work, the only difference is the cabling.
Your host computer (the one that will either be turned on the most or you will be online the most) needs to have 2 NIC's in it.
The first NIC will be used for your internet connection. Plug this directly into your cable modem. Make sure you know which card this is, as you will need to choose it as your internet connection when you run the networking wizard.
The 2nd NIC in the host maching will A. run to your switch, or B. run to the other computer. I will assume that you are going to go to the switch since that is what you have and also what I use.
You will need TWISTED PAIR cabling going from your computers to the linksys switch. Read more about cabling
here
Now, turn on both computer when this is all hooked up this way. On your HOST machine run the home networking wizard. Select your first network card as your broadband connection and your other network card as the connection to your home network. If you feel confident in XP you can let windows choose your network connections...
I don't recommend this though as it usually does odd things.
when that is done, click finish without making any disks or anything. That computer should now be able to access the internet
now, go back into network connections, right click the 2nd network card (the one connected to the switch), and select properties. select Internet Protocol (tcp/ip) and hit properties.
Click "use the following IP address" and enter 192.168.0.1 and for subnet mask use 255.255.255.0 select ok and ok again
Now, start>settings>control panel>network connections
Select the network card that is connected to the cable modem , right click and select properties.
Select the advanced tab, uncheck internet connection firewall.
Under the "internet connection sharing", make sure both boxes are checked.
Now, goto your 2nd machine, start>settings>control panel>network connections.
right click on the local area connection icon and select properties.
Click on Internet Protocol (tcp/ip) and select properties.
Click "use the following IP address" and enter 192.168.0.2 and for subnet mask use 255.255.255.0
what setting the IP address's to 192.168.0.x does is puts them both on the same network allowing them to see each other. this MUST be done to share files and your internet connections)
now reset both machines.
when both machines are completely started and logged into windows, run the home networking wizard on your 2nd machine.
The first thing you will need to choose is your internet connection. It should automatically choose your shared connection if you have everything done right. click next. it will ask you for your connection to your network. again, if you trust XP to choose, then select next again. other wise select "I will choose my connection to the network" and click next. now select the Local area connection and click next until it says computer name and workgroup.
YOUR WORKGROUP NAME MUST BE THE SAME ON BOTH MACHINES. YOU CAN CHANGE THIS AT ANY TIME BY RIGHT CLICKING ON YOUR 'MY COMPUTER' ICON ON THE DESKTOP, SELECTING 'COMPUTER NAME' AND CLICKING CHANGE.
now, finish running the wizard. when it is done, both machines, in theory, should be connected to each other and both should be able to use the internet. if not, post your problem here and i will try to help best i can. also, make sure you check out the sticky thread above and looking through the help pages it links to, they are very helpful. good luck
Oh yea, if you do have problems, the first thing to check is your hardware, make sure all NIC's are in the PCI slot all the way, your cables are plugged in all the way, etc. i spend 8 hrs one day figuring out why my comps couldnt ping each other and all i had to do was push the NIC in all the way
