Updating Win7 caused problems open Win10

I have been using Win 10 for about 2 months. Before I installed Win10, I cloned
my hard drive that has Win7 on it just in case Win10 didn’t deliver as promised.
Monday I thought I’d update the Win7, so I open the PC case, disconnected the
wires from the C drive and connected them to the Win7 hard drive. I opened
Win7 and updated everything on the drive that needed it, like the OS, the Nvidia
driver, Malwarebytes, etc.

I then disconnected the Win7 drive and returned it to its box. I reconnected the
Win10 drive and powered up the PC. I saw the BIOS screen, then a black screen
with “Loading operating system…” and nothing more. “Loading operating
system…” stayed on the screen 5 minutes until I shut the PC down and restarted
it. Same result.
I powered the PC down, checked that all the connections were solid, and tried
again. Same result. I gave up.

Tuesday AM I tried again with the same result. Then I restarted, opened BIOS,
and instructed the PC to boot from the hard drive. Success!
Then I restarted the PC just to be sure and it would not open again. I had to go to
BIOS and specify the boot procedure again. Why it not opening as it has done for
the past 2 months?

John

CountMike,
Sorry. I'm not that technically knowledgable. I do not understand your response nor how it leads me to a fix.
John

When you are in the BIOS menu you can also reset the boot order as well as select which drive to boot from. I think you need to update the boot order to make sure it recognises the W10 hard disk again..

philc43,

When I get to the boot menu, Hard disk is the 3rd item listed and there is a + next to it. I click that and get a page with my 2 hard drives listed, The Win10 HDD is listed first and the Linux HDD is second. There is no + next to the Win10 drive. Should there be? I don't remember if there was in the past as I don't often get into BIOS. Do you think that there is a setting in BIOS that says "always open the first HDD listed"?

John

Can you indicate what the first and second items are in the boot priority order? I think something is trying to bootup ahead of your hard disk and it might well be a UEFI setting as suggested by @CountMike. If possible try to change the boot order and make your hard disk first in the list.

The plus sign is just because you have two hard disks and is the way to access them as you did.

I found boot priority in CMOS and all is well now. Thanks.
John