How to use activation key from Windows 8.1 on Windows 10

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How to use activation key from Windows 8.1 on Windows 10

Emblazer 0

Hi there.

There is an old Acer laptop with Windows 8.1 Home for one language preinstalled, I have a screenshot of an activation key of it (20 symbols) and another Windows account which is associated with this licensed version of Windows. I failed to update from Windows 8.1 to Windows 10 on this laptop, because its HDD ceased to function. Now I want to upgrade the laptop by putting SDD in it instead of HDD, and I worry that Windows 10 that I`d like to install instead of Windows 8.1 will not accept the activation key from Windows 8.1, as it contains 25 symbols, not those 20 symbols I have in Windows 8.1.

Can anything be done about this case? Is there a way to somehow exchange one activation key to another without needless purchase?

Thanks for help in advance.

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Answer 1

Emmanuel Santana 33,160 Independent Advisor

Hello. Since your Acer laptop came with Windows 8.1 preinstalled, the license is stored in the laptop’s firmware, not on the hard drive. Create a Windows 10 USB installer and begin the setup. When prompted for a product key, select “I don’t have a product key,” and be sure to install the correct edition.

As long as the motherboard is the original one, Windows 10 should activate on the new SSD automatically without needing to buy or enter a key.

More info on activation: https://support.microsoft.com/en-us/windows/activate-windows-c39005d4-95ee-b91e-b399-2820fda32227

Emblazer 0 Reputation points

2025-12-12T12:53:15.5+00:00

Thank you very much for your answer!

I have searched a bit more on the issue and found out that the key on my screenshot (just from System window) is not the Windows activation key, but the Product key or something else, and these keys are not the same thing. Moreover, in order to view the activation key, some specific programms should be used. So now I only hope Windows 10 will grasp the key from motherboard (BIOS?) and utilize it properly as you have told me.

Again I`m very pleased with your answer and wish you all the best!

Answer 2

To use your Windows 8.1 activation key on Windows 10, you should be aware that the activation key from Windows 8.1 is typically a 25-character key, which is standard for Windows operating systems. If you have a 20-character key, it may not be a valid Windows activation key, as Windows product keys are usually 25 characters long.

When you install Windows 10, it should automatically activate if the device was previously activated with a genuine copy of Windows 8.1. If you are installing Windows 10 on a new SSD, you can enter your Windows 8.1 key during the installation process. If the key is valid and associated with the same edition of Windows (e.g., Windows 10 Home), it should activate successfully.

If you encounter issues with activation, you can also try the following:

Use the Windows Activation Troubleshooter: After installation, if Windows 10 does not activate, you can go to Settings > Update & Security > Activation and use the troubleshooter to resolve activation issues.
Contact Microsoft Support: If you have difficulties, contacting Microsoft Support can provide assistance in activating your Windows 10 installation using your Windows 8.1 key.

In summary, ensure you have the correct 25-character key for Windows 8.1, and during the installation of Windows 10, you should be able to use it to activate your new installation.

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How to use activation key from Windows 8.1 on Windows 10

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