Windows 10: How do I get digital license again with new installation?

So, my laptop came with preinstalled windows 8 which I upgraded to windows 10. Now there is a trojan which is extremely annoying and doesn't goes away even with professional security softwares. If I format my hard drive and re-install windows 10 then it will ask for product key which I don't have. So, I would like to know if I install windows 8 and then again upgrade it to windows, will it work? Is this option still available? Otherwise how I can install genuine windows 10 with product key?

:)

 

Transfer digital license from old PC to New one.

You would have to first ensure the Digital License is linked to your Microsoft Account. See instructions how to do that. You can then use the Troubleshooter on the new computer after installing Windows 10 to restore the license.

• Use a Digital
  License to Manage and Activate Windows 10 Anniversary Update

Please note, if your license was upgraded from a OEM preinstalled Windows 7 or Windows 7 license, it is not transferable.

See:

• How to Transfer your Windows 10 License to a New Computer

 

digital license

Windows 10 Digital License

When you upgraded from a previous version of Windows or receive a new computer preinstalled with Windows 10, what happened is the hardware (your PC) will get a digital entitlement, where a unique signature of the computer will be stored on Microsoft
Activation Servers. The Windows 7 or Windows 8 genuine license you were previously running will be exchanged for a diagnostics key.

Anytime you need to reinstall Windows 10 on that machine, just proceed to reinstall Windows 10. It will automatically reactivate. You will prompted to enter a product key a couple times through the installation, click I don't have
a key and Do this later.

There is no need to know or get a new key, but if you have issues with Digital Licensing or the Activation Troubleshooter, you can utilize an existing Windows 7 or Windows 8/8.1 product key you already own to
reactivate if necessary. or use the reset function in Windows 10.

Activate Your Windows 10 License via Microsoft Chat Support

Reinstall by Performing a Direct Clean Install

If Windows 10 was already installed and activated on your system, just proceed to perform a direct clean install as described in the following articles.

Step 1: How
to download official Windows 10 ISO files

Step 2:

• How to: Perform a clean install of Windows 10

 

Digital License

Windows 10 Digital License

When you upgraded from a previous version of Windows or receive a new computer preinstalled with Windows 10, what happened is the hardware (your PC) will get a digital entitlement, where a unique signature of the computer will be stored on Microsoft
Activation Servers. The Windows 7 or Windows 8 genuine license you were previously running will be exchanged for a diagnostics key.

Anytime you need to reinstall Windows 10 on that machine, just proceed to reinstall Windows 10. It will automatically reactivate. You will prompted to enter a product key a couple times through the installation, click I don't have
a key and Do this later.

There is no need to know or get a new key, but if you have issues with Digital Licensing or the Activation Troubleshooter, you can utilize an existing Windows 7 or Windows 8/8.1 product key you already own to
reactivate if necessary. or use the reset function in Windows 10.

Activate Your Windows 10 License via Microsoft Chat Support

Reinstall by Performing a Direct Clean Install

If Windows 10 was already installed and activated on your system, just proceed to perform a direct clean install as described in the following articles.

Step 1: How
to download official Windows 10 ISO files

Step 2:

• How to: Perform a clean install of Windows 10