Recent changes in security for all recent versions of Windows, has forced a change in the way we integrate our products into Word.
Previously, you were offered a chance to integrate with Word as part of installation. You could also choose to integrate for All Users. The security changes have prevented us from offering the option to integrate for All Users in a reliable way (installing for just the current user is not usually useful in school situations) so we have been forced to change our systems.
Now each user integrates with Word individually. This is not as hard as it sounds.

Pressing Yes at this point is all that is required for a User to perform the integration.
If the user happens to choose No, they can always integrate later from the Help menu.
This can be done at any time and the new Word tab will show up the next time Word is started.
The good news is that this new process is far more resilient and can be actioned by the user. There is less likelihood that technical support will need to be involved.