public bool AddComent(object coment, int row, int column)

  {

    try

     {

       Excel.Range range = myExcel.get_Range(myExcel.Cells[row, column], myExcel.Cells[row, column]);

      if (range .Comment != null)

           {

               range .Comment.Delete();

           }

       range.AddComment(coment);

       return true;

     }

   catch

      {

       return false;

      }

   }