using System;
using System.Threading;

class Program
{
    private static Mutex mutex;
    
    public static void Main( string[] args )
    {
        // Falls Programm schon laeuft neuen Start verhindern.
        if ( IsRunning() ) return;
        
        Console.WriteLine( "Hello World" );
        Console.ReadLine();
    }
    

    /// <summary>
    /// Pruefen ob Programm schon laueft.
    /// </summary>
    /// <returns>True = Programm laeuft schon</returns>
    public static bool IsRunning() 
    {
        // Eindeutige Programmkennung erzeugen
        mutex = new Mutex( false, System.Reflection.Assembly.GetExecutingAssembly().GetName().Name+"_MultiStartPrevent" );
		
        if ( mutex.WaitOne( 0, true ) ) return false;
        return true;
    }
}