Attempting to do something with an extra monitor

[wkingsnorth]

I have 3 monitors and a TV, which are all hooked up to my PC. However I only really use the TV with the PC when using Netflix and iPlayer, so when I don't use it I have to disable the monitor in the control panel so things don't disappear off the screen. My question is, is there a way to disable the TV when it's turned off or similar? Thanks

edit: What about making it so sound coming from apps on the TV comes out of the TV speakers, not my PC speakers like everything else?

 

[wkingsnorth]

Nothing opens on the left screen, it's just I occasionally accidentally lose things.
Also my speakers are attached to my sound card and only the HDMI TV getting sound from the GPU if that helps.