How To Change Windows 8 Product Key To Complete Activation

First, you need to go to the Start screen type “cmd” and right click. Make sure you choose run as “Administrator” from the bottom options.



Once the command prompt is launched with local admin privilege, run the following command to enter your activation key.

slmgr.vbs -ipk YOUR-ACTIVATION-KEY-HERE

You will get a confirmation for the product key that you have entered.

Then, run the following script to activate the product key

slmgr.vbs -ato

Finally you will get a confirmation on product activated successfully.




Now all you need to do is to restart your Windows8

[Simple Way]

There is actually a much easier way of doing the activation in Windows 8, thanks to W7H reader Daniel for pointing it out in the comment.
Just open a Command Prompt (Admin) window, and fire up the following command:

slui 3

And this window pops up, now you can put in your Windows 8 product key and go active it. This also seems to work when you have a new product key that you want to activate.