Windows 10: Transfer of retail windows product key. Will the OEM stay and be used again?

I just built a new pc, I was planning to transfer my retail windows 10 pro on laptop that was once an OEM but upgraded to retail windows 10 pro. What is the most effective way of transferring it and what will happen to my laptop that had it's retail windows removed? The laptop used to have windows 8.

:)

 

Transferring Retail but keeping OEM key's installed?

I'm upgrading my laptop (Razer blade stealth) from the OEM windows 10 home, to the RETAIL version of windows 10 pro. I'm wondering if I take that RETAIL product key, and transfer it to a new computer (example, buying a new laptop), will the old laptop
still have the OEM windows 10 home product key installed after the transfer? Or will windows be illegitimate?

 

Building a new rig to transfer Windows 10 but not sure if it's OEM or Retail

If you upgraded from a retail box copy Windows 7, it has retail transfer rights.

Use the following to see if you can find the original Windows 7 key. If you can't find the original Windows 7 key, you won't be able to transfer it.

Step 1: How to Find Your Product Key After Upgrading to Windows 10

Step 2:

• How to Transfer your Windows 10 License to a New Computer

 

Can I Transfer an OEM Product Key to New PC?


I built a new PC and want to install windows 8.1. For this I need to buy a product key. I was told that OEM product keys are "married" to the motherboard for life.

But lets say I install win 8.1 and use an OEM product key yo activate it. And lets say in the future I get rid of the old motherboard and install a new motherboard. Will I be able to transfer the product key to the new motherboard? Or would I need a retail product key to transfer the key to a new PC or motherboard?