Please do try these troubleshooting steps that may help in solving the issue.
- Start by uninstalling/reinstalling the Sound card driver.
- Go to Device Manager and uninstall the Sound driver.
- Once done, download and install the latest driver from the manufacturers site.
- You also just reboot your laptop once the driver has been uninstalled and it should reinstall automatically upon reboot.
- But if it will not install I would continue with downloading it from the manufacturers site.
- If this will not work do run System Restore and restore it to the date or time when sound was working just fine.
- Here's how to run System Restore: http/support.hp.com/ph-en/document/c03327545
- If System Restore will not work, last option would be to reinstall Windows.