A motherboard change is treated as a significant hardware change, so Windows may no longer find the license that matched the old device.
Try these steps:
- Open Settings:
- Windows 11: Start > Settings > System > Activation
- Windows 10: Start > Settings > Update & Security > Activation
- Select Change product key and enter the 25-character product key again.
- If activation still fails, run Troubleshoot from the Activation page.
- This can help reactivate Windows after a hardware change.
- An internet connection is required.
- The troubleshooter is available only when Windows is not activated.
- If the PC originally came with Windows preinstalled and the motherboard was replaced, a new license may be required. If the original hardware manufacturer replaced the motherboard, the PC should reactivate automatically. If it does not, use the 25-character key from the COA card if one was provided.
- Check that the installed Windows edition matches the license. For example, a Home key will not activate Pro, and vice versa.
If the troubleshooter does not resolve it, contact Microsoft customer support.