Headphone Jack Problem

Morning all, please excuse if this question has been asked before - I did try searching the threads but could not locate anything.

The headphone jack on my Sony Vaio PCG-71211M is only transmitting sound through one channel.
I have tried searching through the internet but I can't find any solution to changing the microphone in jack to a headphone out jack.

There must be a way to do this through the bios?

I would really appreciate any help you can provide.

Many thanks