LG C9 won't connect to PC

[CJStanleyWinter]

Ok, somebody please explain what is going on.

 

I am trying to connect my LG C9 to a windows 10 PC via HDMI

 

When I plug it into the HDMI port on the graphics card, it locks windows on my main monitor and even entering the password just loops back to the lock screen.

 

If I unplug my monitor and just have the TV connected it shows on the TV but also stays stuck in the lock screen loop.

 

The TV is receiving signal as it displays the lock screen.

It's something to do with Windows 10 not playing nice.

 

The TV's firmware is up to date.

The NVIDIA drivers are up to date.

 

Please someone explain this before I lose my $h!t.

 

Thank you 

[Bombastinator]

What I see happening in the video:

 

there are two monitors and some desktop that could be a whitebox.  Whitebox desktop monitor (which I think is set as main monitor) show logged out booted up windows state.  Rather than showing the login pin on top of the desktop background it opens a new screen, implying something weird.  I don’t know what kind or version of windows this is but it’s not the one I have.

anyway the user logs in, then dips behind the back of the PC and does something or other.  The monitor goes back to the background screen because apparently the user instance is different or it has logged off or something. 

[CJStanleyWinter]

Sorry yeah, that video perhaps isn't the clearest thing.

 

It's a windows 10 PC, I logged in whilst the main monitor is connected to show it working, then connect the LG TV via HDMI and it black screens the monitor, and boots me out to the lock screen and won't let me back in.