For those looking to install Windows 8 and run it for 30 days without activating, similar to how it has been done in previous versions of Windows, you are out of luck. Microsoft has eliminated the grace period and now requires a unique product key for Windows 8.
Many customers would use the 30-day activation period to evaluate the software prior to purchasing, but this will be the case no longer. Customers must enter a unique 25-character product key during Windows 8 setup. If a key is not entered, Windows 8 will not install. Once Windows 8 is installed, the operating system will call home and attempt to automatically activate the install. If Microsoft finds out that the key is not legitimate, the Windows 8 desktop background fades to black and a message pops up warning the customer that Windows 8 is illegitimate. In fact, Windows 8 will shut down every hour. Those who downloaded the 90 day trial of Windows 8 Enterprise do not need a product key, because a key was hard-coded into the operating system and was automatically activated once the PC had a live internet connection.Microsoft, Windows 8