Alternatively, launch a Run window and enter “cmd” to launch it. Windows 10 command line. Type the command “ slmgr/dli “ and hit “Enter.”. After a short while, the last five digits of the product key will be displayed in a pop-up window: The command line displays the last five digits of a licensing key. Download the tool, it will download an ISO and burn it on a DVD or write it to a USB pen drive. Follow the on-screen instructions, skip entering the key and proceed. After installation, Windows 10 HOME should activate fine using Digital Entitlement if Win 8.1 Home was ok initially. Let me know how this goes for you. Windows will activate your Windows license from this information. Make sure the version installed is same as it was previous. For example, if it was Windows 10 Home, you need to install Windows 10 Home only not Windows 10 Pro. If at any point during installation it asks for the key, choose you will do it later on / skip. Step 1. Download and install this program, and then launch it to get its main interface. Step 2. Click Get Key.Then this tool will search all the product keys on your computer including Windows installation, Microsoft Office and etc. Even I tried to get product key using windows.old folder but it says. SOFTWARE. This file is in use. Enter a new name or close the file that's open in another program. That same product key you see is a diagnostics key and all machines get it when they upgrade. When you upgraded from a previous version of Windows or receive a new computer preinstalled with Windows 10, what happened is the hardware (your PC) will get a digital entitlement, where a unique signature of the computer will be stored on Microsoft Activation Servers. Click Command Prompt (Admin) At the command prompt, type the following commands: slmgr.vbs -ipk xxxx-xxxx-xxxx-xxxx (allows you to replace the current product key with the specified) xxxx-xxxx-xxxx-xxxx - represents your product key. Hit Enter on your keyboard. Exit the command prompt. Restart your computer. Designed for users of Windows 7, Windows 8, and Windows 10, our embedded product key tool will retrieve and display the Windows setup product key embedded in the BIOS or EFI, allowing you to store it for safe-keeping or use it to reinstall Windows with an official Windows setup image." With WMI: From the command line, type the wmic (and Enter) Inside WMI, Type OS. Look over "SerialNumber" value. It contains your Windows 8 ProductID. P.S.: Alternatively, you could also type wmic OS from cmd and search for "SerialNumber". Reference. psa81Z.