Windows 10 Pro Won't Activate

Hi Everyone,
I'm new to this site and this is my first post.
It looks like a great site.

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!

Wudevr said:

Hi Everyone,
I'm new to this site and this is my first post.
It looks like a great site.

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!

First, welcome to TenForums.

What version of Windows 10 are you running? Depending upon when you used the Media Creation Tool you may have downloaded and installed Windows 10240 which does not support using a Win 7 Ultimate product key to activate a clean install.

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

Wudevr said:

Within a few minutes the issue was resolved and my Windows 10 Pro is now activated!
Thanks again for your help

I would run Showkey Plus from this forum and see what product key you have. If you have a Product Key different than the generic product key I would hold on to that.

Solved Showkey - Windows 10 Forums

Thanks for the reply NavyLCDR.
I observed the Remote Assistance session from MS and made note of my Win 10 license key which was visible during the activation process
I was aware of keyfinders, but not aware of 'Showkey' specifically.
It's a good tool. Thanks again.