[SysAdm]Change Windows 8 Product Key and Activate - lifuzu/cafe GitHub Wiki

Run cmd as administrator then:

C:\WINDOWS\system32>Cscript.exe %windir%\system32\slmgr.vbs /ipk TYPE-YOUR-KEY-RIGHT-HERE

You will see:

Microsoft (R) Windows Script Host Version 5.8
Copyright (C) Microsoft Corporation. All rights reserved.

Installed product key TYPE-YOUR-KEY-RIGHT-HERE successfully.

And try this:

C:\WINDOWS\system32>Cscript.exe %windir%\system32\slmgr.vbs /ato

You will see:

Microsoft (R) Windows Script Host Version 5.8
Copyright (C) Microsoft Corporation. All rights reserved.

Activating Windows(R), Professional edition (a-long-guid-here) ...
Product activated successfully.

REFERENCE:
http://social.technet.microsoft.com/Forums/windows/en-US/3bdc0d84-fbc9-40a8-91a2-cbfd85888458/change-windows-8-product-key-to-activate