I had the exact same problem on my now-gone MBA 13".
I sold it to a friend, and she said that the packaging (done by the UPS store) was horrendous and they didn't even attempt to fix the MBA in place to keep it from getting bumped around. I was unable to realize this problem because the employee at UPS took the laptop and packaged it inside a room, where I could not see... It was working absolutely fine before I shipped it, so we figured the problem must have happened because of the shipping. Fortunately, no visible marks on the laptop itself.
I looked up every possible solution and told her to try it out (it was her first ever Macbook and she was excited, I didn't want to let her down so I tried hard to fix the problem) even suggesting shaking the thing. Nothing worked.
She had to take it to a Genius Bar and they tried some of the stuff I already suggested her to do, which of course did nothing. They had no clue what went wrong, so their solution was to replace the parts they thought were problematic. It cost $280 USD but she was able to get it done for free despite being out of warranty because the Apple employee there messed some things up with the Serial Number, told her she was under AppleCare (I was very confused since I knew I didn't purchase one) and that the repair would be free. Apple found out it wasn't under warranty and sent her an email with the bill. Upset, my friend called AppleCare and told them the situation... you know the rest of the story.
Anyway, she just received her laptop back and she says they replaced the logic board and...ISO? Apparently they were faulty somehow. Your problem is probably logic board as well. You can't fix it yourself if SMC reset isn't working. You have to take it to a Genius Bar. I hope you have warranty for the laptop.
