Are you talking about 4.1 and 5.1?
If so, the OS has little to nothing to do with it. As long as you are able to load the appropriate drivers for your sound card (integrated or PCI) then the OS should work with the software and it will work. This will involve a little setup within a sound configuration interface of somesort...but it should work. Personally, I've had up to 6.1 work with 2000 Pro.
I believe I used a Sound Blaster card though.
-Michael