PPT97: NewShow Method Doesn't Start Slide Show If Viewer Running

    Sub StartShow()

      ' Change the path and file name to specify the presentation
      ' you want to open.
      Const PRESENTATION_NAME As String = "c:\test.ppt"

      ' Used for error trapping.
      On Error Resume Next
      Err.Clear

      ' Declare the variables used in the message box.
      Dim strPrompt As String
      Dim strTitle As String

      ' Declare a variable to store an object reference to PowerPoint
      ' Viewer.
      Dim oViewer As PowerPointViewer.Application

      ' Loop until GetObject fails. GetObject fails when no instances
      ' of PowerPoint Viewer are running.
      Do

         ' Attempt to get a reference to the PowerPoint Viewer
         ' object model. If PowerPoint Viewer is running, GetObject
         ' returns a reference.
         Set oViewer = GetObject(, "PowerPointViewer.Application.8")

         ' If GetObject succeeds, prompt to quit the PowerPoint Viewer.
         If Err.Number = 0 Then

            ' Set up the strings used in the message box.
            strPrompt = "Please quit all instances of Microsoft" _
               & " PowerPoint Viewer 97 " & vbCrLf & "and click retry."
            strTitle = "Quit Viewer 97"

            ' Display the message box.
            Dim lResult As Long
            lResult = MsgBox(strPrompt, vbRetryCancel + vbExclamation, _
               strTitle)

            ' If user clicked Cancel, end the procedure.
            If lResult = vbCancel Then
               Exit Sub
            End If

         End If

      Loop While Err.Number = 0

      ' Reset the Error object if needed.
      If Err.Number <> 0 Then
         Err.Clear
      End If

      ' Launch and get reference to PowerPoint Viewer.
      Set oViewer = CreateObject("PowerPointViewer.Application.8")

      ' Start a presentation in PowerPoint Viewer.
      oViewer.NewShow PRESENTATION_NAME, ppViewerSlideShowManualAdvance, _
         msoTrue

   End Sub