Old laptops hav this boring tendency of wearing out - no joking. That is connectors attached to the mainboard is often physically mounted in a way so the soldered pins are subjected to force every time a stereo plug is pushed in and pulled out. Over the years, the solder tin weakens and often resulting in lost common connection of audio.
My old Lattitude (but not anchient) suffers from that problem, and it turns out that it affect both external speakers and the internal one, pressumably because the stereo jack plug is a common connection point.
You may be able to hear sound if you trick the computer to play oly one channel, eg. left. It won't go stereo but unless the stereo socket is completely loose, then you should be able to hear at least voices. That is a very temporarly solution and you can't expect it to last for long.