maybe OT: Performa 6200CD needs network help

Hi folks, I've got a friend with a Macintosh Performa 6200CD, and we can't get the network card to function. We've upgraded to OS 9.1 (though we may back it down to 8.5/8.6, it's really really slow now) and when that didn't work, I tried installing a driver package from Farallon (for Ethernet Comm Slot LC? I know this isn't an LC but it was the only thing I could find that was even close to sounding like the right thing). The end result of that was, in the TCP/IP control panel, there are options for "Ethernet slot 1" and "Alternate Ethernet" but neither one accepts an IP address (when we select DHCP, on a known-good DHCP network, it thinks for a few seconds and then says "no valid network address available" or something, and AppleTalk refuses to switch to that interface, and a manually-assigned, known-valid IP also fails). When I hit the Info button in that same control panel, it says Hardware Address Not Available. That seems bad. If it recognizes the card at all, it ought to see the "hardware" (MAC) address in any situation, right? There is a green LED lit up on the card itself, and the LED on the hub lights up too...we tried re-seating the card, no change...tried reinstalling OS 9.1...tried disabling the "Apple Built-in Ethernet" extension...no dice. Anyone have any ideas? I wrote down some cryptic info off the card itself, nothing obvious to me about the manufacturer or model ("SONIC-T"..."BD-059 Rev A"...?) Thanks in advance, -- MB