Today I tried to install Windows 10 on another SSD drive, a 1TB Samsung 870 that I bought a long time ago. This is to start changing from W7 to W10, currently working with both, and also installing Ubuntu on the same W10 disk.
My surprise is that installing W10 on another disk has modified the boot of the disk where I had W7 and damaged it so that it no longer started. I got a W10 W7 dual boot screen to choose from, but the boot for W7 doesn't work, it gives errors.
So I had no choice but to resort to the last Windows 7 backup that I was able to make on July 13, fortunately it worked and I recovered the disk with W7, and the good thing is that now the backup works again even without doing the chckdsk /f /r. It seems that when recovering from a disk image, it is loaded onto useful sectors of the disk, avoiding damaged ones, and this allows the backup to work again.
What has bothered me a lot is that the installation of Windows 10 on another disk has modified the boot of Windows 7, when both are on different disks, and the worst thing is that this dual boot does not work for W7.
Now I will begin to gradually install, in Windows 10, all the programs that I am using in Windows 7 and when everything works, I will definitely start working in Windows 10. I also want to try installing Ubuntu for a dual boot W10 - Linux.