I will try to throw out a few things because I don't know the specifics of them problem.

It would help to know a few things, like the other OS's on the LAN, or if your just trying to connect to a cable modem/dsl.

If you are trying to connect to other computers in a LAN make sure you try to ping yourself in the command prompt. ping 127.0.0.1

This is to check to see if tcp/ip is installed and working properly.

Also are you sure the connection isn't working at all, or can you just not see a shared folder on the other computer? If that is the case it could be because windows 95/98 and 2000/xp take a few extra steps in my experiences for sharing files. Make sure that you create a user account on the windows 2000 box and then make the same account with windows 95/98 to log in to.

Just a few things to try.