Could you find it? When I run Windows 10 wizard ask me for a valid number , , ,
if you can boot a live linux image, then simply run the "strings" command on the virtual file /sys/firmware/acpi/tables/MSDM like so:
# strings /sys/firmware/acpi/tables/MSDM
and the AAAAA-.... is the product key
Please provide us with the model of your product and what happened just before the system crashed so we can have a better view of your problem. Now, in regards of the product key we are unable to gather that for you because if the operating system came pre-installed like in an Intel Compute Stick the only way to restore the product if the upgrade failed is by using the recovery options that appear after pressing F8 when you turn on the device.
Thank you in advance for your help.