Private Sub MainWindow_Loaded(sender As Object, e As RoutedEventArgs) Handles _
    Me.Loaded
    StartButton()
  End Sub

Class MainWindow
 
  <STAThread>
  Public Shared Sub Main()
    Dim app As New System.Windows.Application
    Dim w As New MainWindow
    w.StartButton()
    app.MainWindow = w
    app.Run(w)
  End Sub
 
  Private Sub StartButton()
    My.Computer.Audio.PlaySystemSound(Media.SystemSounds.Beep)
    MsgBox("Hallo du da")
  End Sub
 
End Class