Need help with my headphone jack urgent

My headphones broke inside the jack and now my sound wont work. A small part of the headphone connector is stuck inside the jack and now my computer thinks the headphones are plugged in when they are not and I cant even plug in my headphones into it. I think ill need to take for repair but till then how can I switch off or make my computer give out sound from its own speakers ? Plz help it is really urgent. Thanks!