private void InitializeWatcher()
{
    watcher.NotifyFilter = NotifyFilters.LastAccess | NotifyFilters.LastWrite
                           | NotifyFilters.FileName | NotifyFilters.DirectoryName;
    watcher.Filter = "*.*";
    watcher.Changed += new FileSystemEventHandler(OnChanged);
    watcher.Created += new FileSystemEventHandler(OnCreated);
    watcher.Deleted += new FileSystemEventHandler(OnDeleted);
    watcher.Renamed += new RenamedEventHandler(OnRenamed);
    watcher.EnableRaisingEvents = true;
}

private void OnDeleted(object sender, FileSystemEventArgs e)
{
    SetBalloonTip("File Eliminato");
    notifyIcon1.ShowBalloonTip(1);

    ((FileSystemWatcher)sender).Deleted -= new FileSystemEventHandler(OnDeleted);
    timerRepeat.Interval = 500;
    timerRepeat.Elapsed += new ElapsedEventHandler(t_Elapsed);
    timerRepeat.Start();
    }

  void t_Elapsed(object sender, ElapsedEventArgs e)
    {
        ((System.Timers.Timer)sender).Stop();
    }