From this thread on MepisLovers : http://mepislovers.org/forums/showthread.php?t=15379
It seems I caught Diamond Multimedia playing fast with their downloadable drivers. As far as I'm aware ATi never wrote support for RadeonHD cards in Windows 2000. Part of the problem is that Microsoft held back Win2K Service Pack 5 to keep Windows 2000 out of synch with Windows Xp, and force those using 2k Pro to upgrade to Xp to continue to use the latest hardware... annoying considering that as of 2k pro Service Pack 4, the OS was synched to Xp Service Pack 1.
Anyways, one of the posters on Mepislovers stated he saw Diamond Multimedia offering RadeonHD support on Windows 2000. So... I went to check it out. It is possible some vendors to modify their drivers to support a particular hardware platform. Case in point for me is the Asus F3K I have. Asus provided a version of the 8.40 driver for use with the laptop. Newer drivers from AMD/ATi won't recognize the chipset. So there is a precedent for vendors offering support for products that the original Vendor isn't supporting... and lets face it... nobody wants to support Vista. (Sorry Ballmer, but you are wrong).
So, upon downloading the driver provided by Diamond Multimedia... the first thing I noticed is that Diamond hadn't actually compiled the driver on their own... it wasn't a special vendor release. It was the forth release candidate for the 8.43 driver.
Upon digging down to the driver install file itself in the AMD driver package...
It turns out that the download Diamond was offering isn't for Windows 2000 at all... it's not even for Windows Xp. It's the 64bit driver.
Diamond's been in hot water before with consumers, and there's no telling how many consumers bought RadeonHD cards thinking the cards would work under Windows 2000.
On the other hand, Diamond hasn't technically done anything wrong. The disclaimer about the driver pretty much removes Diamond from any responsibility about the contents.
Either way... it's made me a lot less likely to even consider Diamond Multimedia as a source for computer parts.