OFSO, Pelikal, MM and Milo - Thank you all.
The ways of confusers and Google Earth are truly wondrous!!
Have just downloaded a different version of GE with a dl prefix and not only was the d/l much faster but the installation was at least 3 times faster and it initialised and opened without a reboot and, wonder of wonders, NO CRASH!!
Even if someone could offer an explanation, I wouldn't stand a hope in Hell of understanding it! Used to say that 'pooters' is simple - must be - they only deal with 0s and 1s ...what a load of horlicks!