ip won’t connect to peer after reboot

I’ve narrowed down my issue to this: I remove all components from my local area connection, reboot, then add only the tcp/ip protocol component, with no client or service components. Now my Win2K can ping a Win98 PC, and it can ping me. BUT, after I reboot my 2K, 2K can still ping 98, but when 98 pings 2K, the 2k connection status window shows the packets being received, but it doesn’t respond to the ping. What’s going on?