Thanks for your reply Greg. One of the suggestions was to change the language to a different one and change it back again to reset to the default keyboard settings, but this does not fix it.
This is not just a disability feature, it is a bug. If it was a "feature" and not a bug, the
Control panel => Keyboard settings would show that the repeat rate has been changed to 0 and I could change it back, but it still shows the repeat rate as fast so changing it doesn't do anything.
There is no hint anywhere that the repeat rate has surruptitiously, behind the scenes, been set to 0. I think there must be a registry setting somewhere that "knows" it has been changed, but none of the people who have had the problem have ever found it.
364 people have upvoted Jim Boston's solution. Think how many more didn't go back to upvote and how many more users never found it and had to restore their system or are are just struggling along with no ability to use repeating keys.
It almost makes me weep to think of the wasted man hours and frustration for tens of thousands, maybe even millions of users.
Regards and thanks again for taking the time to reply.
Michael 'The Curate'