In the end, it was a seemingly simple problem.
It appears that the 9000F does not like a long USB cable connection to the host computer.
There is a limited option for siting the scanner in my 'office' and it had meant that the supplied cables with the original and new scanners were just that little bit too short. A independent two metre cable was used to get the extra distance to the host computer. Rather than shift the scanner to be close enough to the other test computers I had used another (5 metre) USB a/b cable known to be good with other devices. This cable was subsequently used for all tests. This, as it turned out,
was a definitive mistake.
I'd dedicated quite a few hours this morning to a new installation of win XP on a spare HDD (I'd forgotten what fun it is
) Install the Canon software, connect printer, holds breath..... Same error message as before.
After a few other fruitless efforts at getting a glimmer of co-operation, and almost in desperation, I unplugged the cable from machine A, started up the W7 Dell laptop where success was last observed, and plugged the recalcitrant device in. An error message in the same terms as seen on the XP machines was the result. Aha!
A shorter (much shorter) cable USB cable substituted and immediate success. Scanner then moved close enough to XP Computer A (on the floor), short USB cable used. Success! - confirmed by a test scan. Repeat experiment with Computer C on the other side of the room - Success! Substitute 5 metre USB cable - Error message is back,
Finally test the 5 metre cable on the nearest active USB device - Brother l@ser printer; print test page. Success!
So it looks very much as though the length of a USB cable can mean success or failure with some devices. Perhaps the quality of the cable can be significant also. It's interesting that the Canon supplied cable has ferrite suppression cores at each end of its 1.5 metre length.
I've yet to try the 'good' combination with the original preferred computer OS / HDD installation, because in the frenzy of install / uninstall activities something else has crept into the equation and it's no longer a happy combination. It looks like the 'new' HDD installation might be promoted. All software and updates need to be reinstalled - it's going to be a fun day - or week.
One disturbing thought remains. Was this the problem with the original 5000 scanner? I'll test it one day when I have the fortitude and courage. If the shorter cable works, the results are unlikely to be disclosed to other people in the household
Thank you again for your interest and assistance. The principle has been established. I now need to hit on just how to manage the combination of cable length and possibly quality which will work reliably.
I guess I can learn from this.
Regards,
FoR