hi,
add a label and a button on your Form then on button_click write the following code
private void btnStart_Click(object sender, EventArgs e)
{
Timer timer = new Timer();
timer.Start();
timer.Interval = 1;
timer.Tick += new EventHandler(timer_Tick);
}
void timer_Tick(object sender, EventArgs e)
{
label1.Text = DateTime.Now.ToString("MM dd yyyy hh:mm:ss.fff");
Update();
}