RegistryKey RK = Registry.LocalMachine;
            RK = RK.OpenSubKey("SOFTWARE");
            RK = RK.OpenSubKey("Microsoft");
            RK = RK.OpenSubKey("Windows");
            RK = RK.OpenSubKey("CurrentVersion");
            RK = RK.OpenSubKey("Run");
            Registry.CurrentUser.SetValue("Название_ПРОГИ",ПУТЬ_ПРОГИ",RegistryValueKind.String);
            RK.Close();