how to enter product key for publisher 2013

I appreciate the constructive help, but as someone who is searching google for "change office 2013 product key" coming to a forum where the responses ALSO include "Why do you need to change the Product Key" aren't helpful, either. It would be nice if forums would just answer the questions asked so that they could be a resource to people in the future.

I'll give you my reason:

I have 3 copies of MS Office 2013.

When I go to office.com/setup and enter my newest key it brings me to the download site, where two products are listed (neither of which show which copy of office is which).

To determine which key goes with which download I go to the advanced options and reveal my key.

However, neither are my newest key, so I cannot simply run either installer and have my new key automatically associated.

So, I install another one with the wrong key, but now must change that key in order to activate my product.

I hope this helps contextualize my issue (and I think the other issues in the forum).

So, is there a way to change the product key? I've tried the command line option with no success.

Thank you.

Hello. I just bought a new computer and I installed office 2013 from a HUP email after purchasing the license. I was given a product key and there was a link to download office. I downloaded office and the product was already activated with a different key than the one I was given. I am worried that whatever it is activated by is time-limited or something, and I would like to change the key to the one that I was provided. I can not find any way to do that.

Please tell me how to do so.

Im trying to install Publisher.  The messages I get are I have others programs running so it cannot load.  I don't have anything open and have shut down twice!  Pease help!!