This morning, my laptop was, as usual, showing an average idle running temp of around 76C, which is fairly hot, but didn't seem too bad... until I put it under load, at which point it shut down because of the temp limit of 97C. Much searching of the Internet commenced, trying to find out what might make a W510 overheat and shut down. Perhaps the heatsink on the CPU wasn't seated properly - but you'd think that would have evinced itself sometime in the previous two years of ownership!
Over lunch, acting on a hunch, I removed the keyboard so as to get at the internals, and applied massive amounts of compressed air, sending much dust flying.
New idle temp at bootup: 46C.
This reminds me of a friend's '$20 home repair of your desktop or your money back' idea: such a service would do nothing more than show up, take the machine outside, crack the case and apply an air compressor. Either you make $20 for <5min of work, or you give them their money back - no matter what, it didn't take much time, so on to the next one!