Perhaps the built-in SD slot in the Windows 7 laptop is not compatible with the SD card.
You could retry the SDformatter with both the options on, on the Windows 10 laptop, and read the card also on the Windows 10 laptop. That should work.
What if you use a seperate usb-SD-reader for the Windows 7 laptop ?
Cool I'm glad you found the problem.Notepad++ has an option in the Encode menu : "Encode in UTF-8 without the irritating useless BOM".But perhaps you better store it as ANSI, your sketch probably does not read UTF-8.