C# :: 프로그램 중복 실행

[System.Runtime.InteropServices.DllImport( "user32.dll" )]
  public static extern void BringWindowToTop( IntPtr hWnd );
  [System.Runtime.InteropServices.DllImport( "user32.dll" )]
  public static extern void SetForegroundWindow( IntPtr hWnd );

  [System.Runtime.InteropServices.DllImport( "user32.dll" )]
  public static extern IntPtr FindWindow( string lpClassName, string lpWindowName );

  [System.Runtime.InteropServices.DllImport( "user32.dll" )]
  public static extern IntPtr SendMessage( IntPtr hWnd, uint Msg, int wParam, int lParam );

  [System.Runtime.InteropServices.DllImport( "user32.dll" )]
  static extern bool ShowWindow( IntPtr hWnd, int nCmdShow );

  /// <summary>
  /// 해당 응용 프로그램의 주 진입점입니다.
  /// </summary>
  [STAThread]
  static void Main()
  {
   bool isNew;
   Mutex dup = new Mutex( true, "RunManager", out isNew );

   if ( isNew )
   {
    Application.EnableVisualStyles();
    Application.SetCompatibleTextRenderingDefault( false );
    Application.Run( new Form1() );
    dup.ReleaseMutex();
   }
   else
   {
    IntPtr wHandle = FindWindow( null, "RunManager" );
    if(wHandle != IntPtr.Zero)
    {
     ShowWindow( wHandle, 1 );
     BringWindowToTop( wHandle );
     SetForegroundWindow( wHandle );
    }
    Application.Exit();
   }
  }