If you receive error "0xC004C008" when trying to use Windows 7 online activation, it could be for one of the following reasons:
Your computer's hardware has been changed.
Windows 7 was reinstalled on the same computer.
Your Windows 7 product key was transferred from another computer.
The Windows 7 product key that you're trying to use has already been used on the maximum number of computers that your license allows.
If you changed your hardware, reinstalled Windows 7, or transferred your product key, you'll need to activate Windows 7 using the automated telephone system.
Open Windows Activation by clicking the Start button , right-clicking Computer, clicking Properties, and then clicking Activate Windows now.
Click Show me other ways to activate.
Type your Windows 7 product key, and then click Next.
Click Use the automated phone system and then click Next.
If you're prompted for an administrator password or confirmation, type the password or provide confirmation.
Click the location nearest to you from the drop-down list, and then click Next.
Call one of the available phone numbers listed. An automated system will guide you through the activation process.
When prompted, enter the installation ID that's listed on your screen into your phone's keypad.
Write down the confirmation ID that the phone system gives you.
Under Step 3, type the confirmation ID into the spaces provided, click Next, and then follow the instructions.
If activation isn't successful, stay on the line to be transferred to a product activation agent who can assist you.
You can only transfer your product key to another computer if you purchased a retail copy of Windows 7 separately. If Windows 7 was installed on your computer by the computer manufacturer, you can't transfer your product key to another computer. For more information, check the licensing information that came with your computer or copy of Windows 7.
Most licenses only allow you to install and activate one copy of Windows on one computer, but some allow more. To see how many installations your license allows, check the Windows package (or confirmation e‑mail if you purchased and downloaded Windows 7 online). For more information, see Read the Microsoft Software License Terms.
If you've used all of the installations that your license allows and you want to add more, you can buy additional copies of Windows 7. For more information about how to get Windows 7 in your country or region, go to the Shop webpage. You can also purchase Windows 7 at retail locations.
Article ID: MSW700074