Private Sub Form_KeyDown(KeyCode As Integer, Shift As Integer)
  If Shift = vbCtrlMask And Shift = vbAltMask And KeyCode = vbKeyS Then
    ' Code für "neues Fenster öffnen"
  End If
End Sub

Private Sub Form_KeyDown(KeyCode As Integer, Shift As Integer)
  If Shift = vbCtrlMask+vbaltmask And KeyCode = vbKeyS Then
    ' Code für "neues Fenster öffnen"
  End If
End Sub