Have you tried the sound troubleshooter? Right clicker the speaker icon in the task bar and select the troubleshoot option. I can assume you checked the volume and made sure it was not muted by accident.
If it was working after the update for approx 2 weeks and has now stopped it may be a hardware issue. Try headphones or external speakers and see it you get different results. Also if this is a laptop and you have a Bluetooth speaker you may want to try that as well.