Macbook Air - Sound Not working - No Output device found

Need Urgent Help

Macbook Air (13 Inch - 2014) - MacOS High Sierra 10.13.4

All of a sudden, the sound on my laptop isn't working. My laptop has not fallen anywhere neither had any physical impact. The only change which happened was that I upgraded to MacOS High Sierra 10.13.4.

When clicked on the sound button, it shows the following greyed out box.

Also, when checked in the system preferences. It shows No Output Devices Found.

I've tried the following options.

1. Reset NVRAM - Issue not fixed

2. Reinstall the OS - Issue not fixed

I don't know how to reset permissions and not sure if that works.

I also ran the apple diagnostics and got the following response.

Any help on this is highly appreciated. I cannot afford not to have sound on my laptop as it is a mandatory requirement for my job.

Also, Cannot go to Apple Store so soon to get this fixed if thats the only option left.

Thanks