Got a call from a Customer Service "Case manager" last night. The laptop is being replaced (and upgraded, too). Apparently, the source of all the trouble is a defective CPU and CPU cooling system (system because it involves the CPU shell, heat pipe, radiator, and fan) which was allowing the CPU to stay at or near 90C most of the time. Heat-related side effects took out some of the video card memory and the HDD controller (which then took out the hard drive). Anyway, HP is doing right by me, and is replacing the whole thing (with an upgraded video card and 2 extended-life batteries tossed in for my trouble). The new laptop should ship around Christmas.