Operating System: Windows 2000 (Note: might work with other versions of this os.)
It works with Windows XP (I have it installed) so it should work with Windows 2000. The driver is old enough that it is likely to work with Windows 98 as well, but don't quote me on that.
If you have an Internet Keyboard Pro (and Windows XP), all your buttons will work with this driver, but you wont get the cool fade-in and fade-out of the volume control that Microsoft introduced with the newer drivers (that don't support this keyboard).
Does it work in Vista? I have no idea.
Hope this works for you though.