I've used laptop computers on many occasions in Lhasa. I've never had any problems with the hard drives -- e.g., the hard drive never broke down and its lifetime was not affected by prolonged use in Lhasa. This includes numerous multi-month stays in Lhasa over the years. In fact, in the past I have given two of my old laptops to Tibetan friends in Lhasa, and they have continued to use them for several years with no problems. As such, I think the fears of hard drive problems in Lhasa are unwarranted.
On the other hand, using hard drives (whether in a laptop or a classic iPod, etc) at higher elevations -- such as at Namtso, Everest, or on the train between Lhasa and Golmud -- is probably not a good idea. I've never tried using my laptop at such elevations, but I know several iPod users who haven't been able to get their devices to work at those elevations.