I have now had the hard disk reforomatted and Windows XP was reinstalled.
This was carried out at a local Computer Repair Shop. They managed to
restore successfully much of my personal date that was not already backed-up
and since then I have been reinstalling many of the programs that were lost.
Lesson - be more careful with the helpful suggestions found on some web
sites and back-up regularly.

Thank you to those people who tried to help me.