Greg;
Whatever you did in the past through command prompt had nothing to do
with deactivating since there is no way to deactivate Windows.
Simply remove Windows from the computer.
When ready, install on the original or another computer (assuming
retail and not OEM) and Activate.
You may need to call Microsoft for activation depending if it is the
same computer and how much time has passed.
If Windows is OEM, you may not be able to install on a different
computer while retail can be transferred to a different computer.
--
Jupiter Jones [MVP]
http://www3.telus.net/dandemar
http://www.dts-l.org
"Sopel" <Sopel@discussions.microsoft.com> wrote in message
news:62C96529-6215-4374-A9B6-C251F16A37A1@microsoft.com...
>I am reverting back to Windows XP, because Vista does not support
>many thigns
> I intend to use. Therefore I want to uninstall Windows Vista.
>
> I was wondering, how do you unregister a product key (through
> command
> prompt) so that you can reuse it again in the future, I did it in
> the past
> but I forgot what I typed in.
>
> Thanks Greg