I have a retail Windows 7 Home Premium license and installation CDs. I'd like to do a fresh install of Windows 10 on an old PC that's currently running Windows 10. If I wipe the machine and reinstall from scratch, will I be able to install Windows 10 and activate with my Windows 7 license, or can I somehow get my activation key out of my existing Wicked 10 installation? Or is it better to just use "Reset this PC"?
If you already have Windows 10 installed, your Windows key is stored on that system. I suggest you take it down before reinstalling windows.
Go to command prompt of your Windows 10 PC and type the following:
wmic path softwarelicensingservice get OA3xOriginalProductKey
This will return you the product key.
I am unsure if your Windows 7 installation will give you an option to upgrade to Windows 10. For good measure, you should go to the Windows website and download Windows 10 installation onto an 8GB USB stick. You should then go to BIOS (F2) and choose to boot from the USB stick to reinstall windows.