Local account, regular password.
If I could launch recovery mode, it would ask me for account password and I would be administrator in such environment. Now, I cannot use SFC command since it report error: Windows Resource Protection could not perform the requested operation. The idea was to use SCF to repair possible driver issue, but it cannot be done, probable due do lack of administrator priviledges on some folders and files which SFC uses for repair. The same was with DISM commands which I solve by changing ownership of WinSxS folder from Trustedinstaller to me and it started working. I have also tried DISM++ I got from MajroGeeks to try slipstream GPU drivers, but it did not work also. Finally, I wanted to uninstall GPU drivers to force Windows to use its drivers in first step, just to go to login screen and enter in Windows 10, where I could re-install GPU drivers. I read somewhere that AMD GPU driver have issue with UEFI mode, meaning that drivers needs to be installed in that mode for proper functioning. Before, my setup was in Legacy mode and probably drivers were setup up for that mode, not for UEFI mode.
Bootlog shows that GPU drivers are problem, but it also did not load Windows drivers, which is strange. If we could, somehow put GPU driver inside and make Windows pull it, maybe it would be solution, but how. Just a thought. Sorry to write this long, I have been fighting this black screen issue for three weeks, so far.
