My MacBook Air Just Shut down and won't start!

Hi Friends, my apple mac book air just shut down while I was working on it. The charger was plugged in. It is a 2009 model. I did the SMC Reset and PRAM Reset. When I press the power button it gives out a beep sound. It did start for a few minutes after the SMC Reset and it also booted for a few seconds after PRAM Reset. but it again shut down. I bought this laptop from a neighbour last year who has left the country where I am, thus, he is not in touch anymore. Please Help me in fixing it. Any help is appreciated. Thanks!