No output/input sound options

I have a 13'' macbook air with a 1.3 GHz Intel Core i5 processor and a memory 4 GB 1600 MHz DDR3 and storage capacity of 251 GB. My computer has recently stopped making sound at all. There are no output/input options in the sound preferences. I have recently installed the latest OS X 10.10.3 Yosemite update. There are no devices shown. No internal speakers and anything.

Things I have tried:

Restarting

Rebooting in Safe Mode

I tried doing a PRAM reset but there is no start up chime

Plugging in earphones

Repairing Disk & Disk Permissions

deleting specific preference files

Installing latest updates

Audio Midi

I need help. I am out of options