If you have installed Windows 8 Developer Preview, the first thing you might want to do is activate it. Activation promises certain benefit, such as the ability to customize your lock screen and access additional services. There are two ways to Activate Windows 8, Metro or using the Classic interface. Lets start with metro.
On the Start screen, click on Control Panel
If you are connected the Internet, Windows will automatically begin the activation process. If not, click the Activate by phone link.
Press Windows key + Pause Break key on your keyboard to take to the System Properties window. Or hover your mouse pointer over Start, click Search, enter system properties, click Settings to filter your search query and click the result.
Click Activate online.
Thats it. The new metro style is obviously much quicker, whichever method you choose, that’s how you can activate Windows 8.