Q: Macbook Air often freezes then shuts down by itself

Hi all,

My macbook air is only 2 1/2 years old, so it's not that old.

I don't know if it's something to do with yosemite but I'll just comment that once I upgraded a few months ago, problems like freezing started.

Anyways... sometimes it can just freezes and would unfreeze itself a minute later and other times it would just shut down without warning and I would have to press the "on/off" button several times until it starts again. And on the other times its both!

What's wrong with my laptop?!?! Please help!

Thanks!