Network Problem

Hey all
Since i built my computer I have been having fight with other family members over the internet as our router broke and we have to plug right into the modem (only one can connect at a time). Today i purchased a 8 port 10-100mbps network switch (Buying a router is not possible at this time) I connected the modem to the switch, then my computer and then the home computer. When i connected on my computer, everything was fine (I have vista ultimate x64 sp2.) I then disconnected and connected the home computer (xp Pro sp3) Everything worked fine. Then I came back to mine and tried to connect and after a bit of waiting i got the message "Error 815" and that the server is not responding. When I do the opposite and connect my computer and then try connect the xp computer, I get the message "Error 676 the line is busy."
I can browse both the computers files through network as long as I have the other computers password.
Does anyone know a solution to my problem so that both computers can be online at the same time e.g. a shared internet connection from vista pc to xp pc or connect to the internet through the other computer and vice versa?
Any help would be greatly appreciated!
P.S Both computers have kaspersky internet security but i tried disabling them and it still didnt work

Generally a switch is used for a large wired network like a college or small/big business office. A switch only multiplies your router ports from the usual 4 ports to 8 or 10 like you've got, there are switches with a larger number of ports as well, 50 and 100's. The router is what splits the INTERNET connection with out the router the switch is no good. The price of the switch is almost the exact same as a router, $50 or less. See attachment, wireless router that you can also hardwire as well from Walmart.

Agreed. Buy the linksys.

If you're up to a little excitement, you can install DD-WRT - a linux opensource firmware solution.
DD-WRT :: News
But it helps to have experience with a wireless router.

The reason you can access your files still is because you have a local only connection. I dont think I switch works off of a modem. I think it goes modem > router > switch > machine. I could be wrong tho.

Ok, I understand now, thanks for all ur help. Ill go buy a router when possible

No problem