Microsoft Word is not now nor has it ever been a part of any Windows
operating system. If you received it as part of a bundle, it was in
addition to the operating system even if it was included on an image of the
factory install.
If that was the case, it cannot be installed on any other system. If you
received a separate Word disk, it can only legally be installed on another
system if the EULA (End User License Agreement) allows it.