Sixteen-bit versions of Windows never did preemptive multitasking.
Thirty-two bit versions did and do, for 32-bit applications (but not for
16-bit applications). Windows NT does it for all applications,

No, windows NT does not pre-emptively multitask.

Win NT/2K/XP is better still, and are generally quite good
OS's, but the multitasking is still rather poor compared to several
other OS's on the market.

This is because it only multitasks, but it is not pre-emptive
multitasking. The kernel does not have complete control of each
application.

Not true. Multitasking on all the NT-based versions of Windows is
excellent.

It is very good, but it is not pre-emptive. OS/2, for one, uses
pre-emptive and it is so far ahead and superior to the way windows works,
folks would not believe it. The difference between the two is beyond night
and day.

The difference will prove to be in your definition. The original
definition has been absconded with by microsoft in order to make it appear
that their inferior implementation actually meets the requirements, so if
it is really important that you 'win' that's okay with me.

Mark