In my power settings, in Win 7, I have got "put the computer to sleep" and "hibernate" both set to "never", on mains. Not sure what the precise difference is, or why it still managed to do it anyway, on this isolated occasion. No repetition so far, so hopefully not an early sign something's going wrong, as I first feared. Maybe it was a power outage after all. I've got the sleep function enabled after just 15 minutes, if it's on battery, so the mains wouldn't have to be out very long before it triggered.

We've got some rather major works going on on the nearby railway, at the moment, so I don't know if it's possible they might have done something during the night that could have affected the power. It's not an electrified section, but I don't know if they might have hit something, dug up something, or whatever.

We've had a formal letter through the door about it, with a number to ring in case of problems, but I assumed they were thinking mainly of noise, not disruption to utilities.

T.