Windows 10: Windows 10 digital key reuse

I have purchased a digital key of windows 10 Home and used it on another device. Now I have a new PC and I cannot use my key even though I deactivated my old device with slmgr /upk. I get a 0xc004c008 error. I don't have my old device connected to a microsoft account. Is there a way of getting the key to work, or do I really have to buy another one?

:)

 

windows 7 key reuse

I'm asking the second thing, if I can reuse my windows 7 key on another machine without any problems. (sorry, I see I forgot to mention it in the original post ^^)

 

windows 7 key reuse

Hey guys,

I'm selling my 1 year old laptop (laptop 2 in sig), which came with Vista OEM.
I installed windows 7 on it with a key from MSDN. My best friend(the buyer) will format the laptop before he gives it to his sister, so I wanted to know how I can reuse my key for a new pc in the future.

I googled a little bit, but I couldn't find a clear answer. Will I have to call Microsoft or something?

kind regards,

 

windows 10 key

Thanks but I don't want to do any decrypting. I want to download a Win 10 ISO from Microsoft and install it using my Win 8 key. No other steps required. Is that possible?