Why wont my if statements work?

Hi my if statements wont work here is my code please help?

case WM_COMMAND:
  {

    if (LOWORD(wParam) == 3); {

      std::exit(EXIT_FAILURE);
    }
    break;

    if (LOWORD(wParam) == 1); {

      system("test.txt");

    }


    break;
  }

i just don't get it!