Problem with activating Win10 from Clean Install, and trouble to install back Win7

[Gonzo100100]

Hello,
I have an annoying problem. I thought it would be good idea to move from Windows 7 Pro to Windows 10 Pro and I created a DVD selecting 'Create installation media for another PC' in the Microsoft Tool. I installed new OS on new partition over old ones (clean install) but I couldn't activate the OS, when I type in my activation key I get an alert that states, "You are running Windows 10 Pro. The product key you entered cannot be used to activate this edition. Error Code:0xc004f210 ". So I found out that my license is volume key license and when I understand what it is it makes sense for me because I acquired Win 7 Pro when I was at university but I finished it so I can't get new key for Win 10 from them. So as I called Microsoft volume licence support they told me to install my Windows 7 Pro back and upgrade it through "Upgrade now" option however, now I can't install it because I receive the error message, "A required CD/DVD drive device driver is missing. If you have a driver floppy disk, CD, DVD, or USB flash drive, please insert it now.
Note: If the Windows installation media is in the CD/DVD drive, you can safely remove it for this step" and when I click ok I get "No device drivers were found. Make sure that the installation media contains the correct drivers, and then click OK." I tried to install the Win 7 ISO image on DVD and flash USB but they both don't work. Over few years I changed motherboard to Gigabyte Z77X-UD3H before that when I had my previous one I installed Win7 using the same image file through flash USB but now it doesn't work.


So now I don't know what I can do. Is it possible to apply somehow to Microsoft that my key will work normally on Windows 10. After all for few months I had "Upgrade to Windows 10 free" banner on my screen but now I can't get it to work. Or maybe you can instruct me how to force forward the installation of Windows7 so I could upgrade it from there.

 

[Gonzo100100]

Thank you for your replies but I managed to resolve the problem. However, it all started from the fact that I had Windows 7 Professional from my university but actually the product key I had was for Enterprise version but I didn’t know that (because the key worked with Professional edition) or the fact that upgrade to Win 10 is not available to my version. So I had to come back to Win 7. Anyway, Microsoft tech support explained me a lot so I downloaded Windows 7 Enterprise ISO, installed it without any problem and I’m all right now. I believe that the problem with the Win 7 Pro installation I had was connected to Gigabyte motherboard (maybe there were some drivers missing) because I remember that I installed Win 7 (using the same ISO image and the same USB flash) something like 4 or 5 years ago to the same PC but with different motherboard (across the years I changed few components like motherboards but my SSDs stayed the same).
Finally I knew that I have to use USB 2.0 because 3.0 won’t work so the problem wasn’t that.
Summarising, Windows 10 upgrade unfortunately isn’t free for everyone. However Win 7 in my opinion isn’t obsolete so I am most likely going to wait for the next proper Windows before I spend £180 on it (by proper I mean Windows like XP, 7 and now perhaps 10)