Now that I have updated to Windows 10 my music and videos have no sound, why?

[WPCentral Question]

Now that I have updated to Windows 10 my music and videos have no sound

None of my videos, music downloads, or even tv and radio stations have sound. Also if I watch a clip on YouTube etc...no sound. I am a granny and not a computer boffin and need a very easy to understand solution PLEASE. I do not want to use Groove as I was happy the way it was before the upgrade