public delegate void VoidDelegate(object q);

    class Login
    {
        public void check_log(string login, string password)
        {
            int logAttempts = 0;
            bool loggedIn = false;
            VoidDelegate GO = null;
            while (logAttempts < 3 && !loggedIn)
            {
                GO= VerifyLogAndPass.VerifyPassword(login, password);
                if (GO==null)  logAttempts++;

                else break;
            }
            if (GO == null)
                System.Windows.Forms.MessageBox.Show("Ad'es Amigo!");
            else
                GO(null);
        }
    }

    class VerifyLogAndPass
    {
       public static VoidDelegate VerifyPassword(string log, string pas)
        {
            VoidDelegate VD=null;
            //// cheking.......
            if (true) VD = InterTheProgramm.StartExecutingTheProgramm;
            return VD;
        }
    }

    class InterTheProgramm
    {
        public static void StartExecutingTheProgramm(object q)
        {
            //собсна сама прога поехала................
        }
    }