How to force running only one instance of your application in C#

        // Setup a unique Name for your Application
        static Mutex mutex = new Mutex(false, "My_Unique_App_ID");

        /// 

        /// The main entry point for the application.
        /// 
        [STAThread]
        static void Main()
        {
            // Delay 3 seconds to be sure that there is no other instance running
            if (!mutex.WaitOne(TimeSpan.FromSeconds(3), false))
            {
                MessageBox.Show("Another instance of this application is already running");
                return;
            }

            try
            {
                // There is no other instances running
                // Launch the application
                Application.EnableVisualStyles();
                Application.SetCompatibleTextRenderingDefault(false);
                Application.Run(new Form1());
            }
            finally
            {
                mutex.ReleaseMutex();
            }
        }