No support of perhaps the most common NIC ever?

EXACTLY. My thoughts exactly, in those EXACT words.

To wit:

XP drops support for ISA non-PNP network cards (never mind that this card can function in PNP mode). It took an act of Congress to get the card working under XP in my rebuild/test system.

If I understand the instructions at this site correctly, the OS actually has proper drivers for this card, they just left out the INF file on purpose. So by grabbing the INF file he supplies (swiped from a copy of Win2k), you can install the drivers that were there all along.

I HATE XP.