Install the same Windows 11 edition—Home or Pro—on the rebuilt system, then reactivate it with the original product key or the Microsoft account linked to its digital license.
If the purchase is a retail product key
- Install the same edition previously licensed. A Home license cannot activate Pro, or vice versa.
- Connect the rebuilt PC to the internet.
- Open Start → Settings → System → Activation.
- Select Change product key.
- Enter the original 25-character Windows 11 product key.
Microsoft documents this as the activation method for a retail copy after hardware changes.^1^
The key may be in:
- The purchase confirmation email or Microsoft account order history for an online Microsoft purchase.
- The retailer’s confirmation email or digital locker.
- The card or label inside a boxed retail copy.^2^
If it was a digital license linked to a Microsoft account
Install the same Windows edition, sign in with the Microsoft account used on the failed PC, and then:
- Open Settings → System → Activation.
- Select Troubleshoot. This option appears only while Windows is not activated.
- Select I changed hardware on this device recently.
- Sign in with the connected Microsoft account.
- Select the former device from the list.
- Check This is the device I’m using right now, then select Activate.^1^
A Windows 11 Pro upgrade purchased through the Microsoft Store app normally uses a digital license associated with the Microsoft account used for that purchase, rather than supplying a product key.^2^
If Windows came preinstalled on the failed PC
That is normally an OEM license associated with the original computer’s firmware or hardware, rather than a separately purchased retail license.^3^
If the failed machine’s motherboard was replaced by its manufacturer, it should reactivate automatically; otherwise, a preinstalled license may not transfer to a different system and a new license may be required.^4^
If activation still fails, record the exact activation error shown under Settings → System → Activation. Errors such as 0xC004F212 can indicate that the installed edition does not match the license, while 0xC004F211 or 0xC004F213 can occur after a significant hardware change.^4^
References
- [Windows 11](https://support.microsoft.com/windows/activation/reactivating-windows-after-a-hardware-change#link-your-windows-11-digital-license-to-your-microsoft-account)
- Find your Windows product key
- Plan for volume activation
- [Windows 11](https://support.microsoft.com/windows/activation/get-help-with-windows-activation-errors#most-common-windows-activation-errors)