Reactivate Windows After a Motherboard or Hardware Change

You replaced your motherboard (or another major component) and now Windows shows “Windows is not activated” with a watermark.

Why: A digital license is tied to your specific hardware. A big change — especially the motherboard — makes Windows think it’s a different PC, so reactivation may be needed. Linking a Microsoft account helps the troubleshooter locate a license; it does not change the license’s transfer rights.

Fix 1: Run the Activation troubleshooter and confirm the hardware change

This is the supported reactivation workflow when your license permits use on the changed device. You must be signed in as an administrator with the Microsoft account your license is linked to.

1. Open Settings > System > Activation.
2. Expand Activation state and select Troubleshoot.
3. Select I changed hardware on this device recently, then select Next.
4. Enter your connected Microsoft account email and password, then select Sign in.
5. In the list of devices linked to your account, tick This is the device I’m using right now.
6. Select Activate.

If the device isn’t in the list, you may have signed in with the wrong Microsoft account, or the license was never linked (see the FAQ).

Fix 2: Check the account association that existed before the change

The troubleshooter needs the Microsoft account previously associated with the device’s digital license. Adding an account to an already unactivated replacement motherboard does not automatically recreate that earlier association or grant a new license.

Before a planned hardware change, check Settings → System → Activation on the activated device. Link the Microsoft account there and confirm the status reports a digital license linked to that account. After a completed change, use the account that was linked earlier. If there is no matching license/device, contact Microsoft Support rather than assuming a newly added account can transfer it.

Fix 3: Re-enter a retail product key

If your license came from a 25-character retail key (not a digital license linked to your account), the troubleshooter may not apply. Instead:

1. Go to Settings > System > Activation > Change product key > Change.
2. Enter the same retail key. A retail license may permit transfer under its terms, normally with removal from the previous device; the Windows edition must match. Possessing a key or linking it to an account does not by itself establish transfer eligibility.

If it’s blocked, you may need to activate by phone via the Get Help app or Microsoft Support.

FAQ

Can I reactivate an OEM license on a new motherboard? Preinstalled/OEM licenses are generally tied to the licensed device; eligible repair/replacement and regional terms need checking with the manufacturer or Microsoft. Retail terms may permit transfer. Microsoft-account linking does not turn an OEM license into a transferable retail license.

The troubleshooter says my account has no matching device. Sign in with the exact Microsoft account that was on the PC before the swap. If it still isn’t listed, contact Microsoft Support through the Get Help app.

Sources: Microsoft Support — Reactivating Windows after a hardware change, Microsoft Support — Get help with Windows activation errors