Update your post to include full system hardware specs and OS information.
Try running the built in Windows Troubleshooters. The troubleshooters may fix and fix the problem.
(Right click the small speaker icon usually located in the lower right screen corner. Select Troubleshoot sound problems to begin. Then, if necessary, work through the other menu choices to resolve the loss of audio.)
Try reinstalling the audio drivers. Download direct via the applicable manufacturer website. Reinstall and reconfigure. No third party tools or installers.
Try searching for system restore
type "restore" then open "create a restore point"
create a new Restore Point now for C-drive
then open the newest restore point that is prior to the problem happening (if you have one)