Hi Alan,
The Windows key + H is a feature intended for Windows 10 to open dictation. There are no means of disabling it aside from not pressing the keys. However, let's try to disable speech recognition and see if it helps. Follow these steps:
- Press Windows key on your keyboard, type Speech recognition and select the search result.
- On the window that would appear, click Advanced speech options on the left hand pane.
- Under User settings, make sure that the check box for Run Speech Recognition at startup is clear.
Let me know if there are improvements.