A motherboard change is treated as a major hardware change, so Windows may no longer recognize the previous activation.
First, try the Activation Troubleshooter:
- Go to Settings > System > Activation.
- Click "Troubleshoot."
- If you see "I changed hardware on this device recently," select it.
- Sign in with the Microsoft account that was linked to your Windows license.
- Select your PC from the device list, then choose "This is the device I'm using right now."
If Windows still does not activate, to help narrow down the issue:
- What activation error code or message do you see under Settings > System > Activation?
- Is your Windows edition Home or Pro?
- Did Windows originally come preinstalled on this PC, or did you purchase a separate Retail product key/license?
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