Public Declare Function SendMessage Lib "user32.dll" Alias _
    "SendMessageA" (ByVal hWnd As Integer, ByVal Msg As Integer, ByVal _
    wParam As Integer, ByVal lParam As Integer) As Integer
 
    Public Declare Function FindWindow Lib "user32.dll" Alias "FindWindowA" ( _
      ByVal lpClassName As String, ByVal lpWindowName As String) As Integer
    Public Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" ( _
    ByVal hWnd1 As Long, ByVal hWnd2 As Long, ByVal lpsz1 As String, ByVal _
    lpsz2 As String) As Long
    Public Declare Function SetForegroundWindow Lib "user32" Alias _
    "SetForegroundWindow" (ByVal hwnd As Long) As Long
 
    Const WM_CLOSE = &H10
    Const BM_CLICK = &HF5
 
 
    Private Sub cmd_Away_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles cmd_Away.Click
 
        Dim hwndDialog As Long
        Dim hwndButton As Long = 0
        Dim retval As Long
 
        ' Handle des Rechner-Fenster bekommen.
        hwndDialog = FindWindow(vbNullString, "Rechner")
        If hwndDialog = 0 Then Exit Sub
 
        ' Handle des Buttons "2" bekommen.
        hwndButton = FindWindowEx(hwndDialog, 0, vbNullString, "2")
 
        ' Fenster aktivieren und in den Vordergrund holen.
        retval = SetForegroundWindow(hwndDialog)
 
        ' Dann den Button drücken.
        retval = SendMessage(hwndButton, BM_CLICK, 0, 0)
    End Sub