I had that happen to my 6 year old MBP 15". I still use it and it happened a couple times in a few months. I just got a new MBP 15 and so far everything is good. Let us know how things turn out. You can goto Apple and they can help diagnose whether you have a faulty motherboard.
Just because of the Apple image, there are still a few bad apples out of a bunch. There's no such thing as a perfect bunch of apples....haha. That's why we have refurbs!!