@george1421 Hi, thank you for your reply.
yes, I agree with you that windows 8 should be stored in the firmware, but then I just don’t understand why when we fog from win 10 back to windows 8 by the image we have 5 years ago, it then grabs the same key to every computer. ( I fog 5 computers and 5 both have the same exact key ). I tried several ways to get the original key from bios by Powershell, cmd, or even registry and nothing worked. All value is empty or no value

again, sorry for the misunderstanding. I am a student worker and try to fog some old computers for sales. What I thought is the fog, will bring the computer back to the time before we going to join domain, and delete everything sensitive inside of it.
I dont think we still keep the cd. But I will try to see if your way work. Thank you again!

I have some HP pro desk 600 G1 DM with Windows 8 pro sticker ( tiny sticker ). When we purchased it 5-6 years ago, we first fog it, then install Windows 10 and run it inside the server. Now, we going to get rid of them, so I fog it for sales, but after fog the Windows key 8 repeats for every computer ( as the same Windows key ) and I just can’t update Windows 10. Seems like FOG took the first image and run the same key to every computer. Just want to ask if there is a chance to get the key back?