If you know you Office product keys and need to know which key is installed on which machine, you can find the last characters of your key with the following command:
Example for Office 2010, using "cmd" to enter commands:
cd c:/Program Files/Microsoft Office/Office14/
cscript ospp.vbs /dstatus
This should return something like:
Microsoft (R) Windows Script Host, Version 5.8
Copyright (C) Microsoft Corporation 1996-2001. Alle Rechte vorbehalten.
---Processing--------------------------
---------------------------------------
SKU ID: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
LICENSE NAME: Office 14, OfficeProfessional-Retail edition
LICENSE DESCRIPTION: Office 14, RETAIL channel
LICENSE STATUS: ---LICENSED---
ERROR CODE: 0 as licensed
Last 5 characters of installed product key: ABCDE
---------------------------------------
---------------------------------------
---Exiting-----------------------------
Where ABCDE are the last characters of the installed product key.
Link:
http://forums.mydigitallife.info/threads/21760-How-can-I-retrieve-office-2010-product-key