Can you ping each other from both PCs? If yes, then your nic are fine.
Here is from what I learned on Win2000. It doesn't like to comunicate with Win9x machine in pure TCP/IP network. You can install NetBeui protocal on both of your PCs. Make sure you unbind TCP/IP over NetBeui (
http://grc.com) on both machine. Disable NetBeui over TCP/IP. In order words, you use NetBeui for your LAN as file/printer sharing and TCP/IP for Internet.