We have been trying to install the Windows 10 upgrade for days now. After countless tries all we would end up with is errors like the dreaded 80240020 and 80080080 errors.
But in the end the easiest way for us was to bypass Windows Update and swing over to the Microsoft download site and download a small 17MB file that upgraded to Windows 10 easily.
All you have to do is choose which version you need 32 or 64 bit, this will download a Media Creation Tool. After you run this, you just sit back and it will install.
Although it gives you the option of creating an install DVD or USB stick, after we chose upgrade this PC we didn’t do anything else.
Here is the page
https://www.microsoft.com/en-us/software-download/windows10