PowerPoint Ribbon buttons not working after Update 2

Hi I was working away quite happily this morning, with no issues at all with Articulate.

Upgraded to update 2 for Presenter and now the only button that does anything is the Help and Support button. (Those with drop down options also function - but nothing happens when anything is clicked.

If I open a PowerPoint with a Quiz embedded, none of the launch buttons on the quiz page work either.

Here's what I did:

1. Installed the update as an administrator.
2. Restarted my machine.
3. Opened PowerPoint - noticed nothing was working.
4. Checked all Add-ins were active - they were.
5. Deactivated and reactivated them, restarting PowerPoint each time.

I can open Quizmaker and launch previously made quizzes from the shortcut added to my screen, and Engage works the same too. However, noting happens from within PowerPoint since the upgrade.

HELP.