Why isn't MacBook Air booting up at all

Hi guys,

I have a mid 2012 MacBook Air 13", yesterday the battery started to not able to hold charge. The battery has eventually dropped to 0% but was still able to boot slowly with the power adapter but now it has totally died. The mac won't boot at all with or without battery, no beeping, no startup chimes, just nothing at all. Only thing that shows is the orange light on the MagSafe. I've tried resetting the SMC and booting with and without battery but nothing is working. Any idea guys?

Thanks.

Ken