I have been trying to upgrade my Windows 7 Pro PC to Windows 10 all week and with the help of a Microsoft 2nd level Support Tech we were finally successful. His conclusion was that even though there were no corrupted System files on my PC, my PC suffered from a great deal of corruption. I thought this was strange as my PC was always rock solid but he downloaded a utility program called Tweaking.com Windows Repair from Tweaking.com. There were many check boxes on the left side of the app and he checked almost everything except the ones that were specific to Windows 8.x before invoking the repair process which took quite a while to complete. Not sure what all it did but it worked as we were able to get Windows 10 Pro installed on a system that previously choked every time we tried to invoke Windows update. Note that I did invoke the upgrade from a Windows 10 Pro install that I created by downloading the ISO file on my laptop. I wanted to get the name of this tool out there as I had not heard about this utility before and probably would have been afraid to use it had I not seen he Microsoft Tech use it. It seems to me that many people that are having issues installing Windows 1o may benefit from giving this utility a try. Others may find it beneficial to run this utility before they even attempting the upgrade.