Now we're getting there. The service engineer arrived, popped in a new harddisk, listened to my worries about the motherboard being the potential culprit of all this, called his supervisor, and will (normally!) be back tomorrow with a new mobo as well. So after two years of intensive (but caring) use, I'll be left with a new and shiny TiBook, and a mostly refurbished (well, the disk and mobo at least) Evo n600c. Any takers?