NEED HELP: No Sound / Audio "No Devices Found". Tried many solutions, none work

I have had this issue two months back, where my internal speakers just stopped working. I have tried all alternatives and what solved my problem was resetting SMC. This time around, I have been watching some videos when all of a sudden my laptop started acting really slow and was responding in delays for about 10-15 seconds and there was no sound. I quit Safari but that didn't help, so I restarted my laptop. After the restart, it keeps showing as "mute" whenever I try to increase/decrease the sound level.

I have tried the following:

1. Restarting
2. Inserting Headphones
3. Restarting again
4. Resetting PRAM
5. Resetting SMC
6. Deleting com.apple.BezelServices.plist
7. Shutting down coreaudiod in the Activity Monitor
8. Disabling Adobe Flash Player,
9. Re-installing OSX using the Command + R during startup
10. Also tried typing this in the Terminal:

sudo kextunload /System/Library/Extensions/AppleHDA.kext

sudo kextload /System/Library/Extensions/AppleHDA.kext

And restarting it another few times for a good measure.

I've got Mid-2012 Macbook Air and I do not have Boom.

This is getting pretty frustrating now.