I know this is going to sound weird but if you have a Wi-Fi card plugged into your motherboard, it can cause the problem of black screen at 75% lockup. When powered back up the computer continues to the 81% or 82% point then the screen freezes at that point. When manually powered down the computer attempts to recover update, fails, and then reverts to the previous version.
There are several threads that address this issue.
answers.microsoft.com/en-us/windows/forum/windows_10-update/win-10-1709-update-freezes-at-82-complete/3fd40e52-7171-41d5-bab8-de4a5837c3e7
answers.microsoft.com/en-us/windows/forum/windows_10-update-winpc/windows-10-update-stuck-at-81/d0384db0-4c3e-4e65-9c19-6f62dc0ccfaa
answers.microsoft.com/en-us/windows/forum/windows_10-windows_install/my-computer-freezes-every-time-a-windows-10/a6745869-9908-4d90-a14a-cf186f62b4c5
answers.microsoft.com/en-us/windows/forum/windows_10-update/windows-10-hang-up-at-75/5ae468e5-7843-4f37-8211-cc392ef2763b
and more...
What it amounts to is an Anatel Wi-Fi card causes major problems with the Win10 updates since 1607. The easiest workaround is to physically remove the Anatel Wi-Fi card from the computer and then allow the update to run. Just disabling the Wi-Fi card in device manager generally does not allow the update to complete. Nor does disabling or removing the driver. A lot of people have solved their update problem by removing the Wi-Fi card physically from the computer.
I do not know if this will help you. I'm just another very frustrated Win10 customer with a Gateway computer. I am currently on Win10 1803 (originally a Win 7). Removing the Anatel Wi-Fi card allowed me to update to this point.
Please read through those threads to see if it might apply to your circumstance.
I hope this information helps.