Renia,
Apparently the issue is not on the list of issues that test program can detect. Sometimes it works -- this time it could not see the problem.
Try this:
Perform the Hard Reset . Boot the computer and log in
The procedure will not wipe out your data -- this is just a driver refresh to force the computer to read the drivers and software from the Operating System that is installed on your computer.
That may do it.
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You said the problem arose after an Update. You can try "going back in time" to when the sound worked:
Restoring Windows to a Previous Point (Windows 7
Using Microsoft System Restore (Windows 8)
System Restore sometimes works better if you first drop the system into Safe Mode:
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You may have to resort to uninstalling and then reinstalling the audio driver.
Control Panel > set icon view > Open your Audio > right click on your audio driver > select Uninstall
Restart the computer and log in. As you do so, the driver will reinstall itself.
More tips are outlined and explained in the guides provided earlier.