Dell Latitude (7420, 7560, 9420) No Audio Fix
Overview:
The Dell Latitude series has an audio issue where the built in speakers do not produce sound due to Intel Smart Sound Technology. The updates from Dell Command Center, Intel Update, and Software Center do not fix the issue. The issue can be resolved by installing the audio driver from the Dell Website.
Steps:
Open Device Manager as administrator
You would need to open it through Control Panel to get admin access
Open Sound, video and game controllers
Uninstall Intel Smart Sound Audio and all Realtek audio drivers
Note some of the drivers will prompt you to restart but you can restart when you are done uninstalling all of the drivers
Open System devices
Uninstall Intel Smart Sound Technology OED
Close the Device Manager and restart the PC. You will now see a red cross over the audio icon at the bottom left
Navigate to the Dell Website and find the drivers for the specific model you are using
The example here is a Dell Latitude 9420:
Click Find Drivers
Navigate to Realtek High Definition Audio Driver and download+install
Complete installation and restart the machine. Audio should work.