static void Main()
       {
           //if (Environment.OSVersion.Version.Major >= 6)
           //    SetProcessDPIAware();

           Application.EnableVisualStyles();
           Application.SetCompatibleTextRenderingDefault(false);
           bool newInstance;
           using (var mutex = new Mutex(true, "Deine_Anwendung", out newInstance))
           {
               if (newInstance)
                   Application.Run(new MainForm());
           }
       }
       //[System.Runtime.InteropServices.DllImport("user32.dll")]
       //private static extern bool SetProcessDPIAware();
       //Application.Run(new MainForm());