Unpack ISO-image to FAT-32 flash drive with 7-zip
or open it in Windows 10 Explorer and copy to this flash drive,
run utils/win64/makeboot64.bat on THIS flash drive
to make it bootable.
Boot your system from this flash drive in not UEFI mode and, on request,
press key “Y” and “Enter”, then again “Y” and “Enter”.
Screenshot of this old software: