7HP>8Pro>8.1Pro>10 Product Keys

[l33tuc]

I'm sure loads of people have been asking questions about product keys, but I think my situation is a little different...

My laptop originally came preinstalled with OEM Windows 7 Home Premium, I later paid for full 8 Pro (non upgrade version), and used that to upgrade said laptop... Which then went on to update itself to 8.1 Pro... And I'm now at the point of about to install 10.

If I do the upgrade in-place, or do a clean install and use the 8.0 Pro Product Key I assume I will get 10 Pro... But could I use the old 7 Home Premium key instead? I understand I'll end up with 10 Home on the laptop, but would that then allow me to use the 8.0 Pro key to legitimately install 10 Pro on another computer entirely? If this is the case do I need to 'deactivate' the laptop first somehow, or would I need to completely roll it back to 7 first? Or could I just download a 10 ISO, do a clean install on the laptop, punch in the 7HP key, and do the same on another computer and punch in the 8Pro key?

Hope that all makes sense!

Cheers in advance for any advice!