OK, the only thing the internet cannot do, is check to make certain your cat didn't unplug the speakers from the wall.
We would love to help, but we need details about what kind of speakers. Are they USB? Do they have a funky wire that goes to the back of the computer that was given to you eight years ago? What make and model of the computer so we can google the manual and see what keyboard shortcut actually unmutes the PC? Stuff like that!