Under View > Zoom, click the button under "Many pages" and then click a
single page (the top left one) to give you a "1 x 1 pages".
Now if you zoom using the mouse wheel while holding Ctrl, it wont matter
what the zoom percentage is, your page will always be centred.
Unfortunately, it isn't sticky (in my Word 2003), so if you are using a wide
screen monitor, this comes back each time you start a new document. (Anyone
know a registry hack for this???)
You could put the following code in a macro and either call it from a button
on the toolbar, or add it to an autoexec macro in the normal template:
Sub ZomeOnePageWidth()
' Macro to force one page only across the screen width and zoom to 100%.
'
With ActiveWindow.ActivePane.View.Zoom
.PageColumns = 1
.Percentage = 100
End With
End Sub
Another way round this is to have a task pane showing and adjust its width
so there isn't room for two pages side by side at your preferred zoom setting.
Hope that helps.
Cheers
Rich