Safe is one thing, functional is another.

My leaning is towards that it should be ok as W2000 is NT based as is XP, Vista and W7. I can see no reason not to try it. Will all the features work? Testing will tell.

From a quick research the reported reason that W2000 was not included is that it's lifecycle of support had expired.

DA

Thanks, DA

I also found this(dated 2005):
"Another is that some of the security work in IE7 relies on operating system functionality in XPSP2 that is non-trivial to port back to Windows 2000."

Found here:
http://blogs.msdn.com/ie/archive/2005/05/27/422721.aspx