Why won't my MacBook boot?

Hi,

I have a Mid-2010 MacBook Pro 13", which has been my trusty machine for the past five years. It's been a fantastic laptop.

Recently, it began losing the time, and shutting off on it's own. Yesterday, it simply gave up, shut off, and that was the last time I was able to turn it on. Since that, I've been unable to turn it on.

When pressing the power button, the charger light goes green (it was previously orange). After 4-5 seconds it returns to orange. I've tried an SMC reset, to no avail. The battery indicator light is true, and shows as fully charged.

Has anybody any ideas as to how I could fix it? I'm missing my Mac!

Many thanks,

George