This article explains why Windows is not activating after reinstalling a different image of Windows

Elo's Windows All-In-One touch computers which are purchased with an operating system already installed, have the Elo OEM license embedded into the firmware which is tied to the image. If you are trying to re-image these systems with a non-Elo OEM image, even if it is the same build type, the license key will not activate because our activation key will only work with an Elo OEM image. This is a legal requirement from our OEM licensing agreement with Microsoft. 

Example: You purchased an Elo I-Series for Windows 2.0 all-in-one touch computer which came with Windows 10 IoT Ent LTSC 2019 installed; however, you have a different Windows 10 IoT Ent LTSC 2019 image that you want to install which is not an Elo image. In this scenario, Windows cannot be activated because the image is a non Elo OEM image. You will need to either use an Elo image or use the Windows activation key from the operating system image you are installing in order to activate Windows on these systems. 

If you do not want to use an Elo OEM image, we recommend purchasing our NO Operating System products and use your own activation key. You can install the Windows or Linux OS of your choice on those without the OEM restriction.