Hi Santa,

(best to use a non-proportional font to display the posting)

You wouldn't believe how complicated this can be,
but if you want to know the whole truth....

There are 5 kinds of spaces,
you might include tabs if you like.

ordinary         ascW(32)
non-breaking     ascW(160)
em-space         ascW(8195)
en-space         ascW(8194)
¼-em-space       ascW(8197)

What I first do is to delete spaces before paragraph marks.
I think they are of no use.
Why? Cause simple replacement may ruin formatting, held in
the paragraph marks.

Sub PurgeParagraphEnd()
Dim lChr As Long
Dim rPrg As Paragraph
Dim rTmp As Range
Dim sTmp As String
With ActiveDocument
  For Each rPrg In .Paragraphs
     Set rTmp = rPrg.Range
     rTmp.Collapse Direction:=wdCollapseEnd
     rTmp.End = rTmp.End - 1
     While IsSpace(rTmp.Previous.Text)
        rTmp.Previous.Delete
     Wend
  Next
  ' looks good, but leaves a space beore the last paragraph mark
  ' if there was more than one space before,
  ' needs special treatment. Don't know why.
  sTmp = .Characters.Last.Previous
  lChr = .Characters.Count
  If IsSpace(sTmp) Then
     .Characters(lChr - 1).Delete
  End If
End With
End Sub

Thanks for the flowers, by the way,
but not to touch the last paragraph mark
was nonsense. To preserve formatting,
quite the opposite is required.
Delete the last paragraph mark,
after having run PurgeParagraphEnd,
until there isn't a paragraph mark anymore,
preceding the last paragraph mark...

All together:

' ---
Public Function IsSpace(ByVal sTmp As String) As Boolean
Select Case AscW(sTmp)
  Case 32, 160, 8195, 8194, 8197: IsSpace = True
  Case Else: IsSpace = False
End Select
End Function
' ---
Sub PurgeDocEnd()
Dim rDcm As Range
Set rDcm = ActiveDocument.Range
PurgeParagraphEnd
While ActiveDocument.Characters.Last.Previous = Chr(13)
  ActiveDocument.Characters.Last.Delete
Wend
End Sub

Enjoy!