Hi there,

To stop the form code running you need to have some kind of check that this
is the first time its being called.  You could add a string to the document
properties the first time it the document gets opened and then test for that
within the Open event code such as:

Private Sub Document_Open()

Dim DocPropComms As DocumentProperty

   Set DocPropComms =
ThisDocument.BuiltInDocumentProperties(wdPropertyComments)
   If DocPropComms.Value = "" Then
       Call YourFormCode
   End If

End Sub

Sub YourFormCode()

   ThisDocument.BuiltInDocumentProperties(wdPropertyComments) = "Faxed"
   '+ the rest of your code

End Sub

This would at least do what you're after.  If you want to go further you
could add some more code to remove the form module (or any other module come
to that) if it's not going to be used again.....................have a look
at Chip Pearson's site below.  The code is for Excel but is basically the
same for Word.  Might be worth testing it on a copy doc first!

http://www.cpearson.com/excel/vbe.htm

Here's some code adapted from Chip's original:

Sub RemoveCodeModule()
'Requires reference to "Microsoft Visual Basic
' for Applications Extensibility 5.3"
Dim VBComp As VBComponent
   Set VBComp = ThisDocument.VBProject.VBComponents("YourFormName")
   ThisDocument.VBProject.VBComponents.Remove VBComp
End Sub

Hope that helps.

Best regards

John