Yes, the NIC shows in the Device Manager, which even claims "this device is working properly". The NIC is listed in Network Properties, and TCP/IP is bound to it.
Like I said, there is no other indication anywhere in Windows 98 that there is anything wrong with the NIC installation. Only that it does not show in the WINIPCFG list of adapters. Pretty strange.
Now, the "100" LED on the router is not lit, but that's because the Xircom NIC is a 10 Mb/sec adapter (AFAIK), not a 100. However, that LED is supposed to *flash* for 10 Mb/sec connections, and it's not doing that. The reason, I presume, is that the NIC is not really communicating with the router. It's as if the router knows there's something there, but they're just not talking.
The NIC worked fine when connected to a desktop machine, so I am going on the assumption it is capable of working correctly.