audio output stopped working os ubuntu 15.0 64 bit

I have ubuntu 15.10 64 bit os on an inspiron 530 S desktop.
my audio card was replaced.
I have line input, mic input, front spkr out rear spkr out 1/8" mini jacks.
Last time I used this computer was in 2016.
From 11 am to 5 pm on 10-03-2018 the audio was working.
At 9 pm 10-03-2018 I returned home powered up the computer to no sound
I had IT savy friends set up this computer with Linux programs.
I do not understand what to do with this computer and all the Linux items on the computer.
I search the sites to educate myself on what I have and how to use what I have, but I still don't get it.
I've been searching my computer to find a specific audio program that was used as the system audio.
Every time I enter audio programs into system search I get a large list of items.
Reading the forums I see the different types of programs discussed and I have some of them on my computer but which one is the default system program ?>????
Windows is media player
Apple is quick time
What the hell is mine?
when I know what my base program is then I can proceed with troubleshooting my issue instead of guessing.
I was told that Linux was better than windows and user friendly.
I do like some of the things but over all no way!!!
The only reason I'n here now is my windows os crashed and getting it fixed is more trouble than it's worth
Please hep me to educate myself so I can ask the correct questions to fix my issue
Sincerely,
Jim McKee
<email address hidden>