If I plan to upgrade my rig (new CPU and mobo, etc.), do I have to re-purchase Windows?

[meloninja]

So I plan on upgrading my current rig (Full ATX) to a micro ATX build - going off to college. I bought the retail version of Windows 8 when I first built my system, but now I have Windows 10. When I upgrade and reinstall Windows 8, since that's was the most recent version at the time, will I be stuck with Windows 8 or will I have to re-buy Windows 10 to get it? Thanks!

 

[Paul NZ]

Ring MS to activate it after. Because it may need reactivation

 

[Samer1970]

read this

http://www.howtogeek.com/226510/how-to-use-your-free-windows-10-license-after-changing-your-pc%E2%80%99s-hardware/