Private Declare Function RemoveMenu Lib "user32" (ByVal _
        hMenu As Long, ByVal nPosition As Long, ByVal wFlags _
        As Long) As Long
 
Private Declare Function GetSystemMenu Lib "user32" (ByVal _
        hwnd As Long, ByVal bRevert As Long) As Long
 
Private Sub Form_Load()
  mnuHandle = GetSystemMenu(Me.hwnd, False)
  Call RemoveMenu(mnuHandle, 6, &H400&) ' "Schließen" entfernen
  Call RemoveMenu(mnuHandle, 5, &H400&) ' überflüssige Trennlinie entfernen
End Sub