Private Function ApplicationRunning(ByVal name As String, ByVal title As _
  String) As Boolean
    Dim i As Integer
    Dim bLaeuft As Boolean = False
    Dim processes As Process()
 
    processes = Process.GetProcessesByName(name)
    For i = 0 To processes.Length - 1
      If processes(i).MainWindowTitle.ToLower().Contains(title.ToLower()) Then
        bLaeuft = True
        Exit For
      End If
    Next
    Return bLaeuft
  End Function

If ApplicationRunning("Excel", "test.xls") Then ...