Obviously changed something. Check to make sure you haven't inadvertently muted the speakers. Go on your computer in the sound settings in control panel (manage audio devices) and ensure you have them set right.
Follow the directions on this site:
http://www.gilsmethod.com/how_to_resolve_unknown_device_problems Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/larry_1fe25e09c54eece2