Hello bufu,
Thank you for posting on the Microsoft Community Forum.
If you have a genuine Windows 11 product key and you've already used it to activate Windows 10, you can usually use the same key to activate Windows 11. However, the activation status is specific to the version of Windows you currently have installed. If you activated Windows 10 with a Windows 11 key, you'll need to use that key again to activate Windows 11. Each Windows product key is typically associated with only one version of Windows and is used to activate that version.
Note that if you got Windows 11 by upgrading from Windows 10 to Windows 11, and your Windows 10 was activated with a retail key, then your Windows 11 should already be activated automatically. If you install Windows 11 directly, you may need to enter your Windows 11 key during the installation process.
I hope you the information above is helpful.
If you have any questions or concerns, please do not hesitate to let us know.
Best Regards,
Yanhong Liu
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