Hi, BloxxyVidsYT. I'm Robinson, and I’m happy to help you today.

When your dad upgraded from Windows 7 to Windows 10 the new Windows license for Windows 10 was attached to his Microsoft account.

To be able to activate Windows you will need to sign in using the same Microsoft account that was used on the computer during the upgrade from Windows 7 and run the activation troubleshooter and select the option "I changed hardware on this device recently".

1-Select the Start button, then select Settings > Update & Security > Activation > Troubleshoot . The troubleshooter will show Windows can’t be activated on your device.

2-Select "I changed hardware on this device recently", then select Next.

3-Enter your connected Microsoft account and password, then select Sign in. The troubleshooter will only work with the connected Microsoft account.

4-From the list of devices that are linked to your Microsoft account, select the check box next to "This is the device I’m using right now".

5-Select Activate.

I hope this information helps. If you have any questions, please let me know and I'll be glad to assist you further.

Windows 10 Pro must be activated either with a valid 25‑character product key or a digital license. The “wrong key code” message means the key currently stored on the device is not valid for activation.

To resolve this:

1. Check how Windows is supposed to be activated
   • Windows requires either:
     • A 25‑character product key: XXXXX-XXXXX-XXXXX-XXXXX-XXXXX, or
     • A digital license linked to the device/Microsoft account.
   • Details on activation methods and where to find them are in Activate Windows.
2. Try a valid product key if available
   • If Windows 10 Pro was purchased (boxed, card, email, or online), locate the original key (card, email, or Microsoft Store order history) and enter it:
     • Select Start > Settings > Update & Security > Activation > Change product key, then enter the 25‑character key.
3. If the PC is pre‑owned
   • If the PC was bought used with Windows already installed, the seller may have reused the key on more PCs than allowed.
   • Ask the seller for the original Windows DVD and product key and try activating with that.
   • If these are not available, or activation still fails, a new product key or copy of Windows must be purchased.
4. If hardware was changed
   • Significant hardware changes (for example, motherboard replacement) can cause Windows to lose activation.
   • For Windows 10, adding a Microsoft account beforehand lets the Activation troubleshooter help reactivate after hardware changes. If that was not done and no product key is available, a new product key may be required.
5. If no valid key or license can be found
   • If the original product key or digital license cannot be recovered, activation cannot be completed with the current information. In that case, a new Windows 10 Pro product key or license must be purchased.

For detailed guidance on activation issues and error messages, see Why can't I activate Windows? and Get help with Windows activation errors.

References:

• Why can't I activate Windows?
• Activate Windows