Hi,
As most of us know Windows XP was a successful more secure remake of Windows 2000 Professional. But my question is will Windows XP software run on the Windows 2000 OS?
Generally speaking?
Yes. Windows XP and 2k are, at the end, NT systems.
When I had Windows 2000 I’ve tested a lot of new applications for Windows XP (that I did not have at that time) and they worked.
Of course, you’ll find exceptions 
Thats what I’ve thought. I wonder if the new messenger program from Microsoft will work on 2000. Doesn’t matter since I have XP anyway.
I rather suspect that the new messenger program may have security enhancements that might not work on w2k, possibly for some of the other new MS stuff. Even IE 6 SP2 won’t work unless you have XP SP2 update installed. So we are probably to see similar effects in new software.
However, the best place to check this out would be the MS web site.
I do not use Messenger (nor any IM program) but if you mean MSN Messenger 7.5 (or newer) then probably not since 2000 is not listed on this page :
I think he probably does mean MSN as in another thread he mentions signing up for the MSN 8.0 beta.
Thanks, David … my mistake, then. 
Not wrong, I think you read it right that Justin is probably talking about the latest version of MSN, then you are probably correct that it won’t work with w2k.