home Network connecttivity

I am attempting to connect two PC’s to a common ADSL internet connection with MSN Broadband using an Abrescomm 800series modem, with a Linksys 4 port cable/DSL router. The main PC is running Windows ME and the other is Windows 98. I can’t get a connection to the internet when I have the network connected, but get good connection with just one, bypassing the network. I don’t get any display of my network when I click Network Neighborhood.
Could this be a cable, NIC, protocol, or other problems.