However, if I boot normally and then run Windows 10 setup.exe from either the USB or DVD, it does NOT run at all (just like with the Media Creation Tool).

If I boot from either the USB drive or the DVD, I can install a new copy of Windows 10 but, of course, cannot enter a product key that works so that does not help. I was able to create both a USB and DVD setup disk using the Media Creation Tool on a different Windows 7 Ultimate PC so I've also tried using both of those options to upgrade my desktop PC. I've rebooted numerous times and I've also tried running it from that PC, from a network drive and from a USB drive ('Run as Administrator' does NOT work either). After starting the 'tool', I've even let the PC sit overnight to see if it would ever start to run. I've spent the better part of the last four days trying to get the Windows 10 upgrade installed on my desktop. I know it does not start immediately but I have successfully run it on two other PCs with Windows 8.1. When I try to run it, nothing happens after clicking the message that allows it run.

The Media Creation Tool will NOT run at all on my Windows 7 Ultimate desktop and my Lenovo Yoga 2 Pro with Windows 8.1.

Windows 7 ultimate media creation tool