When you upgrade your Windows 10 system to Windows 11 for free, your trusty old Windows 10 key should still be good to activate Windows 10 on another computer. No fuss, no muss. It's like a digital high-five from Microsoft for being a loyal user.Now, if you decide to go the extra mile and grab a fresh Windows 11 license, that's cool too. Just remember to swap out your old key with the shiny new one on your upgraded system.And hey, speaking of keys, if you're ever on the lookout for Windows 10 keys, I stumbled upon this Reddit for Windows 10 key cheap. They might have some sweet deals.