Computer issues boil down to one of two things. Software problems or hardware problems.
Hardware problems tend to be more expensive to resolve and though it's possible your hardware has failed I would encourage exhausting the software possibilities first.
Your computer was working fine and then suddenly it did not. You never answered my question, do you allow for windows automatic updates? And do you allow it to treat recommended updates the same as critical? If so then it is possible that drivers were updated with incorrect replacements; it happens to people quite often. If you know when it was the sound stopped working properly you can even check
Control Panel\System and Security\Windows Update\View update history
and see if any Recommended updates were installed just prior.
Things you might try:
If you go to Control Panel\Device Manager you can go to your sound and open it's properties. In Driver tab try "rollback driver" and if it allows it then reboot and see what happens.
If you actually have the driver that you had been using when the system works then you can also try installing and then using
Driver Sweeper (Use in safe mode) to remove the audio driver and then install the one you have.
You could install and try
Device Doctor and see if it recognizes any drivers that need updated. Now just like Windows Update, Device Doctor is also not perfect so if you use it I recommend you always create a restore point prior to its' use and then to only allow one driver to be updated per use, rebooting after each. If your system should fail to boot then in safe mode simply use the restore point to recover and then skip that driver.
Note: If any of these work, then be sure to change the Windows update settings so drivers will not again be replaced by a Recommended update (uncheck the box).