The only good news was that if it had done this a day later I would have been totally stuck. And I had taken a backup the day before (perhaps that is what caused the problem).
Anyhoo, I'm presently sitting in Terminal 3 at Heathrow with my trusty NetBook in my bag. It has most of what I need on it, thanks to some feverish installing last night. I'm always nervous about going away, but fine once I get on the road. I've never been to Egypt before. This should be fun.