Prior to performing a re-install of the operating system on my computer, I ran NirSoft’s little utility called ProduKey to retrieve my Windows 8 product key. This key is required in order to complete the installation of Windows and is the key that communicates to Microsoft that you legally purchased the operating system software.
Typically what happens is when we get these product keys we end up forgetting where we placed them or where we had written them down. ProduKey makes retrieving the key very fast and easy.
ProduKey is a small utility that displays the ProductID and the CD-Key of Microsoft Office (Microsoft Office 2003, Microsoft Office 2007), Windows (Including Windows 7 and Windows Vista), Exchange Server, and SQL Server installed on your computer. You can view this information for your current running operating system, or for another operating system/computer – by using command-line options. This utility can be useful if you lost the product key of your Windows/Office, and you want to reinstall it on your computer.
Note: The description at the NirSoft site indicates the software will display the key for Windows (including Windows 7 and Windows Vista). Does not indicate Windows 8; however, I can attest that it will work for Windows 8, as well.