Assuming that the entire hard drive has been backed up to elsewhere, and Windows 10 installed, how is the application software back-copied to the newly-loaded disk without over-writing the new operating system?
I hope you're not telling me that installing Windows 10 means losing EVERYTHING that you had on the XP drive.
Is Windows Easy Transfer of any value in doing this?
Windows Easy Transfer is not included with Win 10.
I suggest you copy your files to an external drive.
Win 10 will format your Win XP drive as part of the install. So yes you will loose ALL your files.
Ok, think of it like this if you want the xp machine to run. Plug the disk into the machine, behind the win10 os, make certain it is not marked to be booted from. Then in windows 10 os, go to features and turn on virtualization. You may have to turn that on in bios if it is not enabled in features.
Then after a restart go to start and in administrative tools, look for hyper v manager. Build a new virtual machine, using native network driver, and using the hdd that has the xp os on it as the disk to boot from. Save it. Start it. Now you have xp behind windows 10 and if you wish to use an xp program, shell into the xp machine and run it!