The Windows 10 Upgrade Tool works only to upgrade from Windows 7 to Windows 10.
First, from the Windows 7 computer to be upgraded, download the upgrade tool.
Download Windows 10 Disc Image (ISO File)
Then run it.
Accept the terms.
Choose to upgrade this PC. You can create installation media for another PC, if necessary.
Accept the terms again.
Click install. This cannot be cancelled or reverted.
After the installation is complete, the PC will reboot. The first logon after installation will ask for preferences like the first logon from the factory, however, the files will remain unchanged.