Thank you very much for thoughtfully reminding me of the importance of backing up my computer, by providing me with a Windows Update that knackers my system. I'm happy to report I learnt my lesson a while ago ( after a previous occasion when you reminded me this same way ), and was able to re-install my disc image without problems.
I am currently considering whether to wear a cricket box to the pub tonight, in case some equally helpful soul thinks to remind me how much a kick in the fruits can hurt.