I would take it in and have someone look at the fan that is in the laptop; could be it's bad/gone. It shouldn't suddenly overheat like that? My laptop is only a couple weeks old :-) and was overheating the first few days I had it and dying but I had it sitting directly on my lap (silly me, I thought a laptop could sit on a lap) and, unlike my older laptop, that didn't work.

I think one of the ways they're getting laptop prices down (this one was less than half as expensive as my 5+ year old one) is with "cheaper" parts that "don't matter" as much. I think they're also trying to get more stuff into smaller spaces so are scrimping on needed fan sizes, etc. But now that I'm on my little laptop feet on a flat surface, I don't overhead.

I wouldn't run it very continuously? I tend to be on the computer for hours and hours at a time but now try to turn it off and go do something else very hour or two.