A quick blog post to save others from tears. I bought a used IBM ThinkPad R31 with wlan. When installing Windows XP, all went ok but Windows could not find the wireless card.
I wasted couple of hours while trying to install the "correct" drivers from the official R31 support page.
Then I opened the case and found out that the wireless card's model is Ambit T60H786-W. But googling with that model number resulted in no drivers.
Then I ran up to a forum, and found out that the trick is to install the wlan drivers for Thinkpad R50 (7ywc54ww.exe). Works like a charm.