Question Computer Monitor wont turn on?

[Cygne]

So i was on my computer earlier and everything was working fine, i turned it off, then about an hour later i turned it back on and the monitor wouldnt come on for no reason.the monitor initially turns on and displays a white screen and the logo, and then says 'no signal detected", and theres an orange light coming from the bottom right corner... Ive tried unplugging the monitor wires, and putting them back in, but it still isnt working.
Does anyone have any ideas?
I dont really know much about computers, but i took some photos of it

https://imgur.com/a/dXitWyN

View: http://imgur.com/a/dXitWyN

 

[R_1]

the monitor is not plugged into the GPU.
in photo number 9 the GPU is unplugged, the monitor should plug in here. photo 6 shows the monitor plugged into the motherboard. move the DVI cable to the GPU and try again.
usually the onboard is disabled when a dedicated GPU is installed as shown in photo 9.

if it has been working in the current configuration the GPU is not being used at all.

you have both the HDMI and the DVI connected, you only need one per monitor. the monitors should be connected to the GPU below the motherboard I/O Ports.
does the monitor have an input selection, both cables may have switched the input.