hi , try this one
Try
Dim dateString = "25/11/2006 11:45 PM"
Dim formats As String() = {"dd/MM/yyyy hh:mm tt", "dd/MM/yy hh:mm tt"}
Dim dateObject As DateTime = DateTime.ParseExact(dateString, formats, System.Globalization.CultureInfo.InvariantCulture, Globalization.DateTimeStyles.NoCurrentDateDefault)
MessageBox.Show(dateObject.ToString("dd/MM/yyyy HH:mm"))
Catch ex As FormatException
MessageBox.Show( "Please enter valid date in dd/mm/yyyy format.")
End Try