Can't Activate Windows - How to Activate Windows Manually
Either you are performing a new installation or re-installing an operating system that you already possess and you are unable to activate it here is a manual way to do it.
This process does not need any third-party application rather we are only going to use the ever reliable and useful CMD app that is built-in in every version of Windows Operating System.
So, let's begin.
STEP 1: In search menu or Cortana type CMD, right click it then choose "Run as administrator"
STEP 2: We need to remove any existing product key (in case you used a trial key; which is always the case if your operating system is a paper license where your operating system is downloaded from Microsoft), enter and run the command slmgr.vbs /upk by pressing enter key.
STEP 3: We need to clear the product key from registry by running slmgr.vbs /cpky then press enter.
STEP 4: After deleting the product key you need to enter your new product key, use the command: slmgr.vbs /ipk xxxxx-xxxxx-xxxxx-xxxxx where the x’s are your actual product key then press enter.
5th AND FINAL STEP: Activate Windows by entering the command slmgr.vbs /ato then press enter (Windows will be instantly activated).
That's it, it is done.
NOTE: If activation is not reflecting immediately on you computer's settings you may need to restart your computer to refresh it.
Installing Windows 11 on this PC is not recommended and may result from incompatibility issues. If you proceed with installing Windows 11, your PC will no longer be supported and won't be entitled to receive updates. Damages to your PC due to lack of compatibility aren't covered under the manufacturer warranty. In my experience, I say it's better to stick to Windows 10. For example, I don't want to do an update because I have a Windows 10 enterprise key, and it allows me to use programs with all the included features.
If you are using some suspicious free licenses then I am not surprised that there can be such problems. I bought my license here and had no problems with activation. Best of all, the price is really great so I can recommend this store: https://royalcdkeys.com/products/windows-11-pro-oem-cd-key