You may experience a situation where your sound stops working or does not work correctly after a Windows update. Performing the following steps will help you resolve the issue.
Cause information is not available.
Run the Windows Audio Troubleshooter which is found in this Microsoft Knowledge Base article, Fix sound problems .
If the issue persists follow these steps. Instructions for each step are detailed in the Microsoft Fix sound problems article by selecting the topic headers from the drop-down menu.
For additional information, reference the Dell Knowledge Base article How to Troubleshoot No Sound on Computer or Audio Playback Issues.
Here are some recommended articles related to this topic that might be of interest to you.