Question Custom Built PC - BIOS opened once via installation disc, now no signal to display

[minty_fresh]

I recently decided to get the parts together for a custom built PC, and on the first assembly, I got everything plugged in, booted to BIOS via the installation disc, and forgot to flash the bios while it was open. When I tried to boot back in to get that done, the PC wouldn't send any display signal to my monitor.
I've tried other cables, I've tried the motherboard HDMI slot, I've tried booting without the GPU, I've reseated just about every piece in the machine, and tried popping out and plugging back in the CMOS battery. Still no dice.
Monitor itself works just fine with other devices, and the PC itself doesn't seem to have any issues booting up - save for the DRAM and CPU lights each turning on for a few seconds on startup.
Here's the build I'm working with: https://pcpartpicker.com/user/mintingitup/saved/xqnBqs
Any help at this point is appreciated, I feel like I'm losing my mind

 

[rgd1101]

there a bios flash back button on the motherboard. could use that to update the bios. read the manual instruction on that

there is no igpu on the cpu. need to use the gpu