Whats wrong with my PS3?

I was making an emblem in Call of Duty: Black Ops when my PS3 just shut itself off. I unplugged the cords and cleaned some dust from some of the vents. I started it back up and it went to the XMB with no problem. I have a 120GB slim. Did it just overheat? What happened? It has never done it before. Its only been on for about 6 hours. All I've done on it was watch Netflix and play Black Ops.