Why does the system with SSD stop loading when connecting hdd?

Question

Hard disks

Good afternoon.
Input data:
Initially, there were 2 HDDs on the computer, each had windows 10 OS.
When installing the OS, only one hard disk was inserted into the computer, this was done so that the system loaders did not depend on each other.
During computer startup, I could choose which disk to boot from.
Then one HDD failed and was replaced with an SSD, and windows 10 was installed on it in the same way.
After that, a working HDD was connected.

The essence of the problem:
After booting from the HDD, the ability to boot from the SSD disappears, even when the HDD is removed - a message appears stating that an error occurred while loading the SSD and suggest using windows recovery tools.
None of the recovery tools help, restore points are not found, an attempt to restore the launch fails.
We have to roll the system over again.
I tried several times, after connecting the HDD and booting from it - there is no way back.
The system on the HDD is new since the new year, I doubt that it is infected with something.

Tell me which way to think?
Does it make sense to install a bootloader like grub4dos or something like that?
Or the reason is not in the bootloader at all?

Answer 1

I think it's worth connecting an SSD and trying to boot from another HDD. Pull out of the laptop or ask a friend. If the problem persists, then perhaps the bootloader complains that Windows on the hdd is installed in Legacy mode, and not in ahci, which breaks. This item can be toggled in the BIOS. Search the Internet.
Ideally, take a third drive and write Windows from under the same computer to both the SSD and the main HDD

Answer 2

Is it really a software problem? I had a channel conflict on the board