Why can't I activate Windows?
If you received a message saying that
Windows couldn't be activated, here are a few reasons why it might not have worked, and some things you can try to fix the problem. For more info about activation errors, see Get help with activation errors.
For additional help with the activation process, contact support.
You upgraded to Windows 8, but didn't have a previous version or the correct edition of Windows installed (error 0xC004F061)
If you see error 0xC004F061 when you try to activate Windows 8, it means one of the following:
You're using a product key to upgrade to Windows 8, but a previous version of Windows wasn't on your PC. To upgrade to Windows 8, you need to have Windows 7, Windows Vista, or Windows XP already installed on your PC.
If you formatted or replaced your hard drive, you won't be able to use a product key to upgrade to Windows 8. You'll need to install your previous version of Windows, and then reinstall Windows 8.
You’re trying to install the Windows 8 Pro Pack, but you already have Windows 8 Pro installed on your PC. To upgrade your edition, you’ll need to install the Windows 8 Media Center Pack instead.
You’re trying to install the Windows 8 Media Center Pack, but your PC isn’t running Windows 8 Pro. To upgrade your edition, you’ll need to install the Windows 8 Pro Pack first.
If you weren't able to install the feature pack you bought, contact support. For more info about adding features, see Add features to Windows 8: FAQ.
A different version of Windows or product key might have been used as part of a repair
If you took your PC to a repair shop or to a friend who builds and fixes PCs, it's possible that a different version of Windows was installed to complete a repair. Or if the repair shop or your friend used a different product key for your PC, that key might be blocked if it was used on more PCs than the Microsoft Software License Terms allow.
If Windows was activated before you took it to the repair shop or your friend, then re-entering the product key that came with your PC or original copy of Windows might solve the problem. You can also try reinstalling your original version of Windows.
One copy of Windows might have been installed on multiple PCs (error 0xC004C008)
If you have one copy of Windows and installed it on more than one PC, activation might not work because the product key has already been used on another PC, or it's being used on more PCs than the Microsoft Software License Terms allow. Normally, the rule to follow for most copies of Windows is 1:1, meaning that one copy of Windows can be installed only on one PC.
If your product key is being used on more PCs than the Microsoft Software License Terms allow, you'll need to buy a product key for each one of your PCs in order to activate them.
If you have a counterfeit copy of Windows that wasn't published and licensed by Microsoft, activation won't work because Microsoft won't be able to create a match between your PC's hardware profile and your 25-character product key.
The How to Tell webpage on the Microsoft website can help you figure out if your copy of Windows is counterfeit. If it is, you'll probably need to buy a new copy of Windows.
If you bought a used PC with Windows already installed on it, it's possible that the product key is being used on more PCs than the Microsoft Software License Terms allow.
You might need to ask the seller you bought the used PC from for the original Windows DVD and product key. If the DVD and product key aren't available, or if you tried them and still can't activate, you might need to buy a new key.
If you made substantial hardware changes to your PC, such as replacing your hard drive or motherboard, you need to contact support to activate Windows by phone.