Did you try using the compressed air to clean out the vents yet?
I know factually that certain Dell laptop models have had this issue of dust accumulation rising temps., and causing them to crash(not to mention that it COULD happen to ANY ..electronic with fans >.<).
Also, if you know, what model is your laptop?
What kind of temps is the program that Falcon linked giving you? I reinforce that being a good program for Dell Laptops(I have a 600m(w/o these pesky fan errors >: D))
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And yes, as Dayjo said, in the end, some devices are just more prone to the fan being.. blocked
.