If you have or can get the windows license number or key number from your win7 machine, you can load Windows 10 for free. You can get the number by downloading and running free software like the “magic jelly bean” key finder: https://www.magicaljellybean.com/keyfinder/
Then go to the Microsoft.com web site to find the Windows 10 download site. Then download and install Windows 10. It will likely run, but only for a limited time without activation. You might be able to activate it with the Win7 key. If that doesn’t work, you will be given a Microsoft number to call, and they will then activate it with a phone call. Your Windows 7 key must be legal.
does it work if your os is oem installed?
Also- windows 10 should run without the key- BUT you won’t be able to customize it and there will be a watermark down i n right hand corner- nag screen- small, but obnoxious- there is a way to get rid of it though-