Hello, thank you for reaching out to Microsoft Q&A.
Microsoft has already ended the free upgrade from Windows 8.1 to Windows 10. Starting 2025, using the Media Creation tool to upgrade your PC to Windows 10 without affecting your Personal files works in most cases.
- That is, download the Media Creation tool here-
https://www.microsoft.com/en-us/software-download/windows10
- Run the MCT tool and select 'Upgrade this PC now' and follow the prompts to install Windows 10 on your device. If you're using an OEM license, the key will be automatically activated during the upgrade.
However, if this method fails, you will need a USB drive (minimum 8 or 16GB) and create a bootable installation media using the MCT.
You will have to choose the "Create installation media for another PC" option and select the USB drive to make it bootable.
Once created, boot your device from the USB drive and install Windows 10 on your computer.
Note - Reinstalling Windows via the USB drive will delete all your files and apps. Also, upgrades from 8.1 to 10 often activate successfully with a valid OEM key embedded in the system.
However, it is important to note that support for Windows 10 will end in October 2025, and you will no longer receive security updates. It is recommended to use a device with Windows 11 that meets all the modern security and system requirements to ensure continued protection and access to the latest features.
Let me know if you still need mor ehelp.