Computer Turns On but No POST

[kai.scott9173]

I recently upgraded my pc so i got a new mb, cpu, and ram. Ever since this upgrade my pc has been turning on but not posting. All the lights and fans are on but the screen says no signal. I have tried booting the pc several different ways but no luck with all of them those ways being; just cpu mb and psu(this was for a issue that has stopped now)/ only one stick of ram (trying each of them individually)/ everything but the gpu plugged in/ and tried different monitors. While all of this hasn't worked i tried resetting the cmos and no luck there but this is what helped the issue I mentioned. through these multiple tests only once my monitor and keyboard lights flashed for just about a second then immediately turned off but the fans and lights in my pc continued to run. Last thing to add is that my mb has a 8 pin power connector but i'm only using a 4 pin connector is this my issue? All help is appreciated.
My Specs
Gpu: rx580
cpu: r5 1600
ram: 8 gb ddr4 (2x4gb)
mb: asrock x370 pro4

 

[scout_03]

did you use the same set up on the hdd that was set to old board and what is the specs of your psu in the same time check for any debug led on the board .

 

[kai.scott9173]

did you use the same set up on the hdd that was set to old board and what is the specs of your psu in the same time check for any debug led on the board .

i am using the same hdd that i used for the old set up. for the psui i dont know the exact specs put it is a 550w and I dont see any debug lights nor do i see anything about them in the manual.

 

[scout_03]

same hdd without a os reinstall new board need a full os reinstall if it not the same model the gpu ask for a 500 watts psu and did you plug in the 8 pins cable from psu .

 

[kai.scott9173]

same hdd without a os reinstall new board need a full os reinstall if it not the same model the gpu ask for a 500 watts psu and did you plug in the 8 pins cable from psu .

In order to reinstall windows 10 dont I have to be able to get into the bios to do that because if that is the case I cant do that because i dont even have the option to go into the bios. As fort the gpu I do have both the 8pin and 6pin plugged in. As for pluggin in an 8 pin connector the only one i have goes to my gpu and it doesnt even fit in the mb for the part where the cpu gets power.

 

[scout_03]

i ddi read back you only use 4 pins on the board and it need a 8 pins so that could be your issue youhaave to use the 8 atx for the board .