RECOMMENDED: There are a couple of reasons why you’d want to download from Microsoft using your genuine product key. Maybe you’ve lost your Office 2013 DVD and now want to reinstall Office 2013 using the product key that you’ve recovered using a third-party program; or maybe your PC came pre-installed with Office but the manufacturer didn’t offer the required setup file or DVD to reinstall the program; or maybe a friend of yours has given an unused Office 2013 product key and you want to download and install Office suite using that product key. Just like it’s possible to, it’s possible to download Office 2013 program as well. All you need is a genuine product key or if you have already registered your product key using your Microsoft account, you can download Office 2013 by simply signing in to your Office account page, without having to enter your product key.