Win 10 Pro Won't Activate

[wudevr]

My PC was running Windows 7 Ultimate and I wanted to upgrade to Windows 10.
Unfortunately, my PC was in a perpetual "Reboot to finish installing updates" state, so I was unable to perform the upgrade.
I did some research and determined that my Windows 7 Ultimate key (which I legitimately purchased) should allow me to upgrade to Windows 10 Pro. So because I could not upgrade due to the 'updates reboot' issue, I decided to do a clean install. I formatted a USB stick and created Windows 10 Pro installation media using the MS Media Creation Tool. During the install it prompted me for a license key. I entered my Win 7 Ultimate license key, but it was rejected. I now have Windows 10 installed, but it's not activated. What should I do now?
Thanks in advance for your help!

 

[Suztera]

Install window 7 ultimate, activate it and then upgrade to window 10 via window update or the ISO.

 

[noidea_77]

Download the new unified iso from Microsoft. It fixes this problem and works with the Win7 key - or should at least

 

[psoohoo]

you can only use your existing product key when you install a fresh copy of Windows 10 November Update (build 1511), not any of the previous builds.
You will need to create a new ISO with this build or reinstall windows 7 and do an upgrade to 10.

Sadly, Microsoft pull all links to get 1511 directly, unless you have a TechNet account.

 

[wudevr]

Thank you all for your responses.
To answer your question. I'm running build 10240.
I ended up calling MS Support.
They called me back and ended doing a Remote Assistance session.
Within a few minutes the issue was resolved and my Windows 10 Pro is now activated!
Thanks again for your help