using System.Threading;
class Bank
{

  Mutex m=new Mutex();
  public void withdraw()
  {

   m.WaitOne();//this method will allow only one thread at a time
   MessageBox.Show("From withdraw");
   m.ReleaseMutex();//this methos is releasing executed thread features

  }
}
private void button1_Click(Object ender,EventArgs e)
{
  Bank obj=new Bank();
  ThreadStart ts1=new ThreadStart(obj.withdraw);
  Thread t1=new Thread(ts1);
  Thread t2=new Thread(ts1);
  t1.Start();
  t2.Start();
}