................have you tried a different set of speakers or earphones to verify it
is PCLOS?
......and what
version PCLOS are you talking about?
There are sound settings, but it is advised not to fool with those quite yet.....
Also....DUST is a big culprit with computers and equipment....if your speakers have a volume control knob - try to use a small amount of compressed air in and around the knob...there are also various electronic cleaner sprays available online or locally...
...also make sure your speaker {normally green color} plug is clean and all the way "in"....with no breaks/kinks in the wires....

.....

JN.