Timer t = new Timer();
 private void Form1_Load(object sender, EventArgs e)
{
 t.Interval = 15000;
 t.Tick += new EventHandler(OnTimerTicked);
 t.Start();
 }
 public void OnTimerTicked(object sender, EventArgs e)
 {
 t.Stop();
 Form2 formdois = new Form2();
 form2.Show();
 }