PS3 freezing problem?

So I was playing Black Ops just a few minutes ago on campaign, and so the game just froze. So I waited about 1 minute to see if the game would catch up with itself, to see if it was just a minor freeze, it did not. So I then got up and turn off the PS3 from the front button, the green power light flashed a few times, gave me 3 beeps then is still flashing fallowing with a black screen. This has been 5 minutes! I am also kind of worried because it makes this wierd noise, you know how a Playstation does when its like going into a game or thinking. But that sound just goes on. And Im also afraid to turn it off from the back with the power light still on, I dont want to get the YLOD. What should I do?