make sure your'e earphones are plugged into the green socket (not the pink one).
When the EARPHONE WINDOW comes on screen (and earphone plugged in shows up) click the OK box.
If a 2nd window shows up,...... click that Ok box as well.
Now,...... you should have sound through your earphones.
If you havent,........ go to the bottom right hand corner of your screen and you should see a small round bell symbol.
Click it, and then a VOLUME WINDOW should appear. When it does, see if there is a tiick inside the MUTE box.
If there is,....... click inside that MUTE box to cancel it, because that is blocking your sound output.
Give this a bit of a try out and see if it can return your sound.