its either your speakers are broken or somehow you have disabled them ... here is how to check if they are enabled , Control panel>hardware and sound>sound then there should be a box that pops up ... now you pick the audio output you need and enable it (you do this by clicking on it and then clicking on properties)
Where was the sound coming from, speaker or headphones. Can you test them with another device to be sure its not the source of the problem. If they work, then its probably a driver issue or the sound being remapped to another output.