Miscellaneous topics that do not fit into specific categories.
Open the old Control Panel, not the new Settings App.
At the top of the old Control Panel, set View to large icons.
Open the Programs and Features applet.
In the list if installed apps, find Office, select it and click Uninstall.
You should get a notification indicating Office cannot be found and ask you if you want to remove it from the list of installed apps, select Yes.
That process should remove the associated registry key for the Office installation.