Windows 10 Upgrade – How to Upgrade from Windows 7 Home to Windows 10 Pro

I had exactly this problem.

I solved it buy obtaining a new Windows 10 Home key from msdn and then changing the product key (also via the settings-> Activation window). After doing this I then repeating the attempt to update to Pro (with legit key) via the store.

My guess is that whatever I had as a key was not eligable for the upgrade combination i was trying via the store.

Because I've never received any media(CD/DVD/USB/Download URL) from Microsoft when upgrading from 7 Home Premium to 10 Home to 10 Pro nor did I see any product keys from Microsoft for 10 Home or 10 Pro. The only thing I received was the order history on my Microsoft account that has the order number, date of purchase and the amount I paid for Windows 10 Pro upgrade.

Your product key is connected to your hardware. Since you upgraded an OEM copy of Windows 7 Home, you received the rights to Windows 10 Home, which you upgraded to an OEM copy of Windows 10 Professional.

At this point if you wanted to install Windows 10 Professional you would just install it, since you don't have to worry about the installer finding the wrong key ( i.e. Windows 8.1 Core instead of Windows 8.1 Professional ), when ask for a license key you simply skip that step.

If I want to reinstall from scratch I have to start from Windows 7 Home Premium, then upgrade to 10 Home(which was free but isn't anymore), then again up to Windows 10 Pro(using my purchased license I've never seen). Which means, they said, I have to buy Windows 10 Home now to be able to reinstall from scratch.

You interpreted what they said incorrectly. You can indeed install Windows 7 Home, then upgrade to Windows 10 Home for FREE, since Windows 10 ISOs are 100% free. This is possible because your machine has had Windows 10 Home installed on it before. Of course doing this is a waste of time, since Windows 10 Professional was also activated on your machine, you can simply install that.

I can't burn ISO of Windows 10 Pro to a media and install it right away because they said it's an "upgrade key" not full retail license of Windows 10 Pro.

They gave you incorrect information. I don't know what question you literally asked them, it appears you are not clear how Windows 10 itself activates, so lets just move on.

ther rep said: my Windows 7 Home Premium key has been upgraded to Windows 10 Pro key, and that I can use that key on the sticker on my computer to install Windows 10 Pro from scratch via burned ISO on a media.

This is false. A key to one version of Windows 7 cannot install an entirely different version of Windows 10. Windows 7 Home activated before the the offer expired, Windows 10 Home installations, that is all it activated.

Since your machine activation status is tied to a digital entitlement. You can only use a single installation of Windows on this machine unless you provide it an entirely different license key.

Any tool, you normally would use to determine your license key, will return a generic key. It's possible you can get the Windows 10 Professional key, after its been activated, again this will automatically happen since its tied to your hardware.

if I want to reinstall Windows 10 Pro operating system from scratch(without using Reset PC or Refresh PC, just please ignore this option for now) what will I do when prompted for license during reinstallation/activation phase?

You do understand that if you use the Reset feature, the end result is IDENTICAL, to formatting your machine and installing Windows 10 Professional right?

As for a program that might be able to get the correct key for your installation, the only key I have ever known to work, is ShowKeyPlus