Windows 8.1 Black screen prior to login screen

So I've hit this issue where I am welcomed with a black screen which is supposed to be my login screen. It boots up, but what would look like the login screen is simply black. When moving the mouse, the cursor would emerge whilst changing from pointing to loading(cursor animations). The wifi icon from the lock screen seems to flicker sometimes but that's pretty much it, nothing could be done from my end.
I've tried resetting/restoring from the advanced boot options(triggered by constantly interrupting the bootup process) but it's telling me it cannot be done since the location of the OS is not "unlocked". Safe mode with networking/command prompt gives me the same result. Unfortunately, I do not have a system restore point nor a system image to use. The command prompt from within the repair does not let me use sfc /scannow, too.

Brief history of what happened beforehand:
I installed the Uxtheme patcher to enable third-party themes, then before rebooting installed an application called StartIsBack. After rebooting, it seemed fine and I changed my mind and decided to uninstall StartIsBack. It turns out the aforementioned program brings a cavalry of bloatware before you could uninstall it. After I got rid of the extra software it came with, I proceeded to delete each part of StartIsBack from its respective directories, but it wouldn't let me delete its core StartIsBack64.dll, because it is running in the background. There is no sign of it as well within the task manager. So I had to boot to Safe mode to manually delete it and finally getting rid of it. After rebooting normally, the explorer.exe didn't open upon start-up. Opening it manually by launching it from the Task Manager doesn't work either, so I decided to try and use SFC /scannow to try and fix the problem. It reported that it wasn't not able to fix some of the errors found, and changes will take place after the next reboot. After rebooting, I am greeted with the black screen issue.

tl;dr is there a possible solution to this without having to format my os partition and/or installing a new one? If I really have to, is it possible to just delete C:, and perhaps install Windows 8.1 over it? My media files are in D: .

Try this tutorial: http://www.eightforums.com/tutorials/26095-repair-install-windows-8-a.html

CountMike said:

Try this tutorial: http://www.eightforums.com/tutorials/26095-repair-install-windows-8-a.html

Click to expand...

Hi, I am unable to do and follow the tutorial as using the "Upgrade" option prompts a message telling me boot-up normally without the use of the installation disk(in this case a bootable flash drive). And using the repair option from the installation disk gives me the same result as the built-in repair options(refresh/reset).