This example sets the Interactive property to False while it's using DDE in Windows and then sets this property back to True when it's finished. This prevents the user from interfering with the macro.
Application.Interactive = False
Application.DisplayAlerts = False
channelNumber = Application.DDEInitiate( _
app:="WinWord", _
topic:="C:\WINWORD\FORMLETR.DOC")
Application.DDEExecute channelNumber, "[FILEPRINT]"
Application.DDETerminate channelNumber
Application.DisplayAlerts = True
Application.Interactive = True