Thank you, Saab Dastard. I'd love to change it but she won't - yet, anyway. I just hope that her Dad long outlives the computer but I may have a fight on my hands if I am to achieve that.
The machine works just about fast enough for her - certainly until each weekend! - it's self-interest that presses me to ask how to cut down my own commitment to it on each Wednesday afternoon. I get the impression from you experts that changing the order of play would not help me but I am still interested in the viability of doing the defrag and backup at the same time overnight. It would save a lot of hassle but I fear that it wouldn't work and that I wouldn't know for sure until I had to do a restore for real.
I'm sure it was mixture who said that cleaning the registry was a madness. Once I've Cleaned the Crap the "Registry" button in the margin is like a magnet and I often can't resist! Then there's no point in scanning it if you're not going to clean it....
Sorry, mixture, because I think we crossed in the post. The backup takes over six hours with Windows Back up. Perhaps there's something faster but it would need to be uncomplicated too.