Open the Normal.dot template.
Go into Track Changes and accept all changes.
Turn track changes off.
Type the letter "a" and backspace to delete it (not undo).
Save the template and close Word.

Reopen Word.
What happens?

If that doesn't work, try renaming the normal.dot template. See Normal Template in Microsoft Word - How to Open if you need instructions on how to open or find (bottom of page) the normal template.