Computer Randomly Shutting off with Mountain Lion

Im not exactly sure what my problem is... (I have a Macbook Pro circa June 2010)

Basically, with Snow Leopard sometimes my computer would randomly freeze and turn black (the screen would turn entirely black and would lock up), and I would be forced to reboot it. It was tolerable, as it only happened when I was using movements on the trackpad such as one with three or four fingers...

But now with Mountain Lion my problems are wayyyy worse. Not only does it happen when I do trackpad motions, but also just randomly (when I open a new browser, click a button, etc.

It is getting to the point where my computer is almost un unseable, as it will happen as rarely as just once every few hours, or even a couple times every 10 minutes.

Any advice would be appreciated, I hope Im not the only one with this problem. I did thankfully back my HD up before I switched to ML.

Thanks to anyone who can help