Making an ISO image of a hard drive means creating a 1-to-1 backup copy that consists of a .iso file. Here are two ways to do just that.

If you're upgrading from an HDD to an SSD, make the most of the extra speed it offers by setting the SSD as your boot drive.

How do I install Windows on a SSD instead of HDD? To set up Windows on an SSD instead of HDD, connect the SSD and a bootable USB drive with the Windows installation files.

Windows 10 has a concept of a boot folder that gives a logical location for the boot files and that can be confusing if you expect the boot order you set in BIOS to be the final determination.