If you try this in case of windows form then it would be easier than what you think.Pick Timer
control on your form.Then right click on it,you will find properties.At the event tag you will find tick
event which you need to use.Then code just like as..
private void timer1_Tick(object sender, EventArgs e)
label1.Text = DateTime.Now.ToString("hh:mm:ss tt");
And see your clock is ready to operate!One thing need to mention here,you will find interval option in the properties of timer control where you can change interval of your clock.