If you can physically put the cursor at the top of page 8 then Demo3 should work. Otherwise, use Demo4
	Sub Demo3()
Dim oRng As Range
Dim oPar As Paragraph, lngInst As Long, lngUpdate As Long
On Error Resume Next
  Set oRng = ActiveDocument.Range
  oRng.Start = Selection.Range.Start
  For Each oPar In oRng.Paragraphs
    With oPar.Range
      If .Style.NameLocal = "Normal" Then
        If Len(Trim(.Text)) > 2 Then
          If Not .Characters.Last.Previous Like "[.!?:;]" Then
            .Characters.Last.Previous.Select
            lngInst = lngInst + 1
            Select Case MsgBox("Do you want a period here?", vbYesNoCancel, "Add Stop")
              Case vbYes
                .Characters.Last.InsertBefore "."
                lngUpdate = lngUpdate + 1
              Case vbNo
              Case Else: Exit For
            End Select
          End If
        End If
      End If
    End With
  Next
  MsgBox lngInst & " instances found " & lngUpdate & " instances updated."
End Sub
Sub Demo4()
Dim oRng As Range
Dim oPar As Paragraph, lngInst As Long, lngUpdate As Long
On Error Resume Next
  Set oRng = ActiveDocument.Range
  oRng.Collapse wdCollapseStart
  Do Until oRng.Paragraphs(1).Range.Characters.Last.Information(wdActiveEndPageNumber) = 8
    oRng.Move wdParagraph, 1
  Loop
  oRng.Select
  oRng.End = ActiveDocument.Range.End
  For Each oPar In oRng.Paragraphs
    With oPar.Range
      If .Style.NameLocal = "Normal" Then
        If Len(Trim(.Text)) > 2 Then
          If Not .Characters.Last.Previous Like "[.!?:;]" Then
            .Characters.Last.Previous.Select
            lngInst = lngInst + 1
            Select Case MsgBox("Do you want a period here?", vbYesNoCancel, "Add Stop")
              Case vbYes
                .Characters.Last.InsertBefore "."
                lngUpdate = lngUpdate + 1
              Case vbNo
              Case Else: Exit For
            End Select
          End If
        End If
      End If
    End With
  Next
  MsgBox lngInst & " instances found " & lngUpdate & " instances updated."
End Sub