There have been numerous reports of difficulties getting DirectX to run properly in XP with several different NVidia based cards.
I am not personally aware of any specific GF card that does not function under XP.
Remember, that there are many different GF2MX400 cards. Some mfgs use the refernce BIOS and drivers for the GF2 chip. While others customize the BIOS and drivers to "optimize" performance.
NVidia is on their 3rd set of "reference" drivers since XP was released.
I have different GF2 MX 200 cards in 2 different XP machines with no "difficult" problems.
Just download the latest XP drivers from either the card mfg, or Nvidia.
As to the video BIOS, that is only available from the actual company that made the video card.
For some of the more "popular" cards, some of the game and tweak sites may have 3rd party drivers.
Check out www.voodoofiles.com for links.
I have amny a time corrected a video problem by updating the BIOS on the motherboard.
Chas