Thanks Ivo, beginning to trend towards not trying CS for that reason (possibility).
Just looked into the BIOS as it is, and the only option shown under Boot is "Boot Option #1 [Windows Boot Manager]".
I note this does not specify a specific location as to where this is located, for example the 64GB permanent SSD drive.
If a formatted USB memory is present, also shown is Boot Option #2 [UEFI: Lexar USB Flash Drive 1100, Partition 1]".
These can be swapped over.
During the failed
viewtopic.php?f=12&t=6440 routine the only option in the Boot menu was the flash drive. You need to change the BIOS Security setting under Secure Boot Menu from Disable to Enable.
I did not try the Bootmed option suggested as I did not have either of the machine's when informed about that.
For information in normal start up Windows Explorer shows just: "OS (C:)".
The purpose of this entire exercise is make Windows 10 look and operate more like 7. I am preparing the machine for a 76 year old friend, who is familiar with 7, not much chance with 10! He can't work a smart phone, hasn't got one and does not want one.
Another option could be a complete clean install of 7, deleting 10, but drivers may be an issue.
Presumably I could recover/reload 10 as is, through BIOS and the 10 Recovery USB I have already prepared (took about 5 hours!).
Anybody any thoughts?