Product key for Windows 10 is not publicly available.
Product key for Windows 10 is not publicly available.
You can upgrade to Windows 10 using another hard drive without needing a product key from Windows 8. The upgrade tool will handle the process, and you won’t have to purchase a separate Windows 10 license. Just follow the prompts in the Microsoft tool, and it should work smoothly for your current installation.
You're asking about how Windows activation works. It seems you're wondering if using a Windows 8 key for Windows 10 on another machine is valid. That's generally not allowed unless you have the proper licensing or a valid activation method. Let me know if you'd like clarification!