Private 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
 
Private Declare Function PostMessage Lib "user32" Alias "PostMessageA" _
  (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, _
  ByVal lParam As Long) As Long
 
Const LNULL = 0&
Const WM_LBUTTONDOWN = &H201
Const WM_LBUTTONUP = &H202
Dim hdl As Long
 
Private Sub Form_Load()
    Timer1.Interval = 1
End Sub
 
Private Sub Timer1_Timer()
    hdl = FindWindowEx(LNULL, LNULL, vbNullString, "Datei auswählen")
    If hdl = 0 Then Exit Sub
    hdl = FindWindowEx(hdl, LNULL, vbNullString, "Abbrechen")
    PostMessage hdl, WM_LBUTTONDOWN, 1, &H8001F
    PostMessage hdl, WM_LBUTTONUP, LNULL, &H8001F
End Sub

mfg
brave@heart

...bis zur unendlichkeit und noch viel weiter...