Any one Genuine Windows operating system like Windows 10/8/7 or software program such as Microsoft Office 2016/2013 needs a product key while installation and needs an activation key while activation. If you’ve lost the product key, you will be unable to successfully reinstall or activate Windows/Office. In this case, iSumsoft Product Key Finder is the best software which can help find lost product key for installed Windows/software from Registry on your computer. It supports to find product key for any version of Windows 10/8.1/8/7/Vista, Microsoft Office 2016/2013/2010/2007 and other software/programs/applications. iSumsoft Product Key Finder is the most easy-to-use Product key finder software. You just need to download and then install this software on the computer where you lost the product key for the installed Windows/Office or other software. Then launch this product key finder. It will automatically detect all Windows and programs installed on your computer. Then you just need to click the Start Recovery button to start to find the lost product key. Product key should be found and displayed. Clicking the “Save to File” button you can save or back up the product key to a text file.