Can't find Office 2010 product key. How to locate it?

[alecus]

Being my first post here, there are chances to post in the wrong section of this forum. If so, I am asking moderators to accept my apologizes and to move my thread in the right place of this forum.



So here it is my issue with Office 2010: I need to re-install it but I can't find the its box with its key. The store from which I have bought this product told me that there is not much to do and I will have to buy a new license. However, I have found on the internet some information according to which the needed code is still in the Windows Registry of my OS. I have browsed that menu by didn't managed to find anything relevant. Also, I tried one of the tools which are presented by a product key retrieval website...but without too much success.

Do you guys have any idea on how to locate my key?
Thanks a lot for your help.