Second monitor wont be detected?

I’ve had dual monitors for a while now and never had a problem, however, the other day, I installed a new motherboard. After booting it back up, only one monitor had turned on.
I have one monitor plugged into my graphics card, and the other plugged into the onboard slot.

The one that is turning on is the one plugged into the graphics card.

How can I get my computer to recognize the onboard monitor?

Need more info such as GPU, processor, and mobo

GTX 760
intel i5
ASrock z97 killer series

Go into your BIOS and enable your onboard graphics.

I kinda looked around in my BIOS and I found a button about multi monitors so I enabled it, it didn’t help however.

I didn’t see a button about onboard graphics

It might be called integrated graphics

Also try using the onboard as your main monitor, AKA unplug the one connected to your graphics card and see if it works.

Why are you using onboard gpu if you have a 760? You will need to go to your bios though and enable the igpu, onboard graphics, whatever they have elected to call it.

Does your graphics card not have a vga port and an HDMI port? You could just use those. Both display 1080p.