How to activate Office 13?

First Check whether yours is activated by going to File > Account > SEE AT THE THE RIGHT SIDE...

If not activated then click CHANGE PRODUCT KEY and enter any of two keys below.... HAPPY :)

The serial Key is  9MBNG-4VQ2Q-WQ2VF-X9MV2-MPXKV   ---->   will surely 

key source: http://doubtsoncomputer.blogspot.in/2013/01/microsoft-office-13-activation-key.html

{OR}

6KN9D-BDR6R-7FX8R-8J42X-TFXTW ---->  which is given in the below image...