Downgrading windows 10 with activation key

[Kun___]

I build a new computer and i installed windows 10, but im not really satisfied by windows 10 and i bought an activation key for windows 8 pro but i dont know how to downgrade it

 

[Someone Somewhere]

I'm pretty sure you'd need to do a fresh install; you can't downgrade.

You'd need to get hold of Win8 media and boot off that.

 

[Rabmac]

You can download Windows 8 media from Microsoft website: http://windows.microsoft.com/en-us/windows-8/create-reset-refresh-media