Hi zcomputerwiz
Just to let you know that I began getting various other errors other than the Windows Update ones so, in some desperation, I took the bull by the horns and did a second repair (upgrade version) of my Windows SP1 x64 bit OS. I can now say that my pc is 'firing on all cylinders' again and all 203updates are safely installed. I've done a SFC /scannow followed by the SFCFix.exe and all is well, so I can retire tonight and sleep much better. The problems were really getting me down!!
Many thanks for all the help you afforded me and I wish you every success in your chosen profession.
Kind regards and best wishes.
Ray