Until you get more replys from some of the system experts here, you may find this to be of interest:
I've seen that behavior a few times, and it was the result of overheating. Which is NOT to say that there aren't other more likely causes, I dunno. But I do a lot of video encoding, which are processor and hard drive intensive. Therefore I need to remind myself to keep an eye on temperature. Overheating costs me a hard drive occasionally, despite the fact I have two extra fans in my case and never encode to the OS drive. And AFAIK, laptops are prone to overheating anyway, are they not?
You could see what HDTune tells you about the hard drive. That is, if you can somehow connect the hard drive as a slave in another computer, or manage to boot up your laptop. Free, here:
http://www.hdtune.com/download.html
Good luck.
