I have my work laptop setup with Windows 8 and now its time to Activate.
This is how I tried to do this and how I succeeded in doing so

Method 1: Perform the steps mentioned below.
a: Right Click at the bottom left of the screen and select System.
b: Click View Details in Windows Activation under Windows Activation
c: Click Activate

Method 2:
a: Right Click at the bottom left of the screen and select Run. You can also use the shortcut keys *Windows Key and the letter “R”. This will open the run dialog
b: Now type Slui 3 in the Run dialog box and hit enter.
c: Enter your product key here. And Click Activate

Note: Make sure you are connected to the Internet when performing this step.

Hope this helps some of you.

– Jermal