if you use internet explorer, here is the step:

• Click on Validate Windows or Validate Office. If you have both, you’ll need to validate each separately.
• Install the ActiveX control (you only have to do this once).
• View your validation results. If your software is genuine, you can start enjoying the additional benefits of genuine right away.

after that, click on validate windows or validate office on the left menu. 

if you use firefox, you should install required plugin. go to http://microsoft.com/genuine , follow the instruction until finish.