Open the word document,
Press Ctrl+F11 to open VBA Explorer
In the left hand menu double-click 'This Document'
Paste the following code in the new code window
Save and close, then give it a go
If it asks you to allow macros, go look
here, at the bottom of the page, about Digitally Signing a documnt.
Code:
Private Sub Document_Open()
ActiveWindow.View.ReadingLayout = Not ActiveWindow.View.ReadingLayout
End Sub