Months ago I fully overhauled an old laptop for my brother: motherboard cooling upkeep, battery replacement, RAM + SSD upgrade… and a Windows 10 fresh install from an old ISO image downloaded via eMule. The latter point does not really matters; the only difference versus an ISO from an official source is the crack it may contain by default, which is easily uninstalled after first boot and pointless anyway. Such hardware was running Windows 7 before the upgrade, on its old hard drive. The fresh install and upgrade to latest version was of course seamless.

I really do not get why you couldn't “fresh install”. Unless you wanted to get an activation from Windows 7, that is. A single machine valid license can be gotten for ≈$5. O:)

:-)