Which is which, no sound from laptop or no sound from external
speakers?
Try isolating the problem whether is it laptop or external
speakers problem.
Unconnect external speakers from laptop, set sound volume to
mid-range or max range, then try play back mp3 using a media player
of your choice.
If there is no sound from your laptop internal speakers, then
chances are there is a resource conflict in your windows settings,
corrupt sound driver or your laptop's audio processor chip is
spoilt.
If there is sound from your laptop internal speakers, then
problem maybe is at the external speakers. Just connect the
external speakers to another PC / laptop and you will know.