Arrow [Q] Secure Booting Error! Cause: boot certification verify

Hey guys,

I have this error on my LG Optimus G E975.
Im well aware of the KDZ method of unbricking my phone but it seems that I always get stuck because it says "no phone detected"
Is there any way to check if my Windows 8.1 is being a pain or if my USB port is broken or something?

I hear the sound of the phone being connected when I plug it in, in download mode but any Flashtool says Phone can not be detected.
I saw a comment somwhere saying that as long as my computer detects it, I can push a ROM via ADB to it.
I have to idea what that means but would like to try it if it works. ANY ideas are welcome, ive been stuck at this for a week now...

Thanks guys!