This is the sample code I used..... Word.ApplicationClass oWordApp = new Word.ApplicationClass(); oWordApp.Visible = true; Word.Document oWordDoc = oWordApp.Documents.Open(ref fileName, ref missing, ref readOnly, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref isVisible, ref missing, ref missing, ref missing, ref missing, ref missing); oWordDoc.Activate(); Can u plz help me?