Computerworld reports that Microsoft has eliminated the 30-day grace period used in Windows 7, forcing customers to use a legitimate product key immediately when installing the retail version of Windows 8. That's because the upcoming OS handles activation differently, pushing the Redmond company into tossing out the former "evaluation" period.

According to the report, customers installing Windows 8 and Windows 8 Pro will be required to enter a unique product key -- a 25-character alpha-numeric string -- in order to progress to the actual setup menu. If the key isn't provided, then the installation will stop. Microsoft used this same method with the Consumer Preview and Release Preview builds of Windows 8, although Microsoft provided a generic key for these.

After installation, Windows 8 automatically connects to a Microsoft server -- given the machine is connected to the Internet -- to verify that the user's key is valid. If the key is valid, then Windows 8 is activated. If the key is deemed not valid, then the typical non-genuine ritual reportedly kicks in by fading the desktop to a permanent black and displaying a message saying the OS is illegitimate. The PC will then shut down every hour.

For consumers purchasing new PCs with Windows 8 pre-installed, the system will have already been activated, thus the product key steps will only apply to those who are upgrading from an older Windows platform, or are installing the OS on a freshly formatted hard drive. Windows 8 and Windows 8 Pro are reportedly loaded on the same disk image, thus the unlocked version depends on the key that's supplied prior to setup.

For Windows 8 Enterprise, the OS ships with a Key Management Service (KMS) client key that's activated by a local machine. There's also the Multiple Activation Key (MAK) method which is used by codes downloaded from TechNet and MSDN and connects with Microsoft's activation servers. Software Assurance customers can actually take Windows 8 Enterprise for a 90-day free evaluation which does not require a product key.

"For customers who will be deploying Windows 8 Enterprise, be assured that the KMS and MAK volume activation methods that were available with Windows 7 Enterprise are still there and work as they did before," said Microsoft's Stephen L. Rose last week. "But there is also a new Active Directory-based Activation method, offering a way to leverage your existing Active Directory infrastructure to simplify the activation process."

In order to use KMS or MAK activation, users will still need to grab new keys from the Volume License Service Center, he said. Even more, those still using a Windows 7 or Windows Server 2008 R2 computer as a KMS host will also need to install a hotfix to enable Windows 8 Enterprise activation.

Windows 8 and its variants are slated to go retail on October 26, 2012.