I have to say that I am a noob. So, don't be too rude with me

I bought this pc this year with Windows 8 pre-installed. I then upgraded to Windows 8.1.
After I have installed Ubuntu 12.04 LTS, in a normal dual-boot.
A few days ago I wanted to upgrade Ubuntu 12.04 to Ubuntu 14.04 LTS. And I delete completely windows 8.1...... completely.

So I searched for an ufficial windows 8 or 8.1 iso, but I wasn't able to find or install win8 from ubuntu. So I found an ISO for Windows 8 enterprise and I installed it, with a 90 days of trial.
I was able to recover my product key of my official windows 8 from ubuntu, and I try to put it in windows 8 Enterprise and it says to me:
"Your product key works! Continue when you are ready." But when I click to 'Activate', it says to me "The product key you have entered will not work with this edition of Windows. You must either run Windows 8 Setup (??) or enter a Windows 8 Enterprise PK".
Also I can't upgrade to win8.1

So, it's true that I made a mistake, but I have paid for that (horrible) Windows 8, and now I want it back. I want a Windows 8 iso from which I can load my valid product key. Is this possible? I don't want an evaluation version. What can I do?

Hi, that key doesn't function because you're using a core/pro Key on Enterprise Window.
You need to download a Core or a Pro ISO of Windows (depends of the windows edition of the key)

On our blog at this link http://www.windowsblogitalia.com/2013/0 ... 600-16384/ we have only torrents for full italian o.s.
I advice you to search on torrents, that's not illegal because you have the Keys.
I will try to find an english RTM torrent tool (I will update this topic)