Computer boots but monitor has no signal

[PizzaPenguin]

I just built my computer (specs below) and when I press the power button, the computer appears to turn on, as lights turn, fans spin, and I hear one short beep from my speaker indicating a normal boot, yet no signal on monitor. I've tried multiple monitors, multiple cables, DVI and VGA, and tried with onboard video and my graphics card to connect to the monitor. I've also tried with just 1 stick of RAM and tried it in every slot, all to no avail. I've reset the CMOS twice and tried the trick where you unplug the computer and hold down the power button for 20 seconds many times. Each time, the computer boots yet still shows No Signal on the monitor. I took all the components out of the case and tested the bare minimum components with one stick of RAM, the motherboard, the CPU and cooler, and 2 different power supplies, yet it still does the same thing in every scenario. I've run out of ideas and need help.

Specs:

Intel i5 6500
Gigabyte Z170 -HD3P Motherboard
8GB (2x4GB) Crucial DDR4 RAM 2133mHz
1TB Seagate Barracuda
550W EVGA SuperNova 80+ Gold Modular
Gigabyte AMD Radeon R7 250

 

[ingtar33]

have you tried pulling the gpu out of the system and plugging the monitor into the motherboard?

 

[PizzaPenguin]

have you tried pulling the gpu out of the system and plugging the monitor into the motherboard?

Yes I've tried both VGA and DVI outputs from GPU and motherboard alone and into 2 different monitors

 

[ingtar33]

with the gpu pulled out of the system; physically removed, right?

 

[PizzaPenguin]

with the gpu pulled out of the system; physically removed, right?

Yes

 

[ingtar33]

well then your problem isn't the gpu~

the only parts left that can cause this problem are (listed in order of likelyhood)
1) bad motherboard/electrical short
2a) bad ram
2b) bad psu
3) bad cpu

nothing else will stop a computer from POSTING. I am of course under the assumption you clr_cmos properly. I suggest you try another power supply, then i suggest you search for shorts... maybe the motherboard is installed wrong and there is a spacer or something behind it, checked the motherboard visually for signs of stains or other damage like burn marks, check the molex plugs for signs of melting, fire, or lose wires. Check the case switches are properly installed and working

if you have other ram to try, try that.

if you do all of this can can't find anything wrong then i suggest you pick either the cpu, ram or motherboard to return as faulty. My money would be on the motherboard. as usually failed cpus or ram will prevent the system from even sounding like it's booting.