If you’ve installed Microsoft Office 2010, but are wondering where to enter the Microsoft Office 2010 product key, you’ll find it in the Help section of any Office 2010 program.
To enter the Office 2010 product key, once you’ve installed Office 2010, open up Microsoft Excel (or any Office 2010 application), click File -> Help and click Change Product Key on the right hand pane. Enter the product key and click Install Now to complete the installation. This should take less than a minute and Office will now be activated, even though the Help page will still say Product Activation Required. To confirm that the product key was entered correctly and Office 2010 is activated, close Microsoft Excel and reopen it. Then go back to the Help page, which should then say Product Activated.