Private Declare Function ShellExecute Lib "shell32.dll" _
    Alias "ShellExecuteA" (ByVal hWnd As Long, _
    ByVal lOperation As String, _
    ByVal lpFile As String, _
    ByVal lpParameters As String, _
    ByVal lpDirectory As String, _
    ByVal nShowCmd As Long) As Long

ShellExecute Me.hWnd, "open", "DeineDatei.txt", vbNullString, vbNullString, _
  vbNormalFocus