Question Short mobo -- PC won't start?

[Kenzoassasin]

Hi. I want to ask something. I bought a new case and psu for my build. Later when everything were put into, it cannot be started. There is light on cpu led. So i changed thermal paste but the problem still persist. So, I removed usb port connection from front io to the motherboard. There is no light on cpu led.
A new problem came when i connect with the monitor. The led lights again. So what i did was turn on the pc first, and then wait untill all the peripherals turned on, then i turned on the monitor. Is there any connection between monitor and cpu led?

My build specs :
AMD Ryzen 7 2700x
Aorus x470 ultra gaming
Gigabyte 16gb ram cl16
Asus strix gtx960 4gb
Adata sx8200 240gb
Seagate 3tb 7200rpm
Cooler master cm mwe 650w gold
Segotep prime xl

Monitor
Samsung cjg54 27"

P/s: i know the gpu is bottleneck to my cpu. I'm planning to change it later. It's from my older build. Sorry for bad English

Thanks

 

[Lutfij]

You may want to see if breadboarding the system with the bare minimum(meaning one stick of ram, only boot drive and CPU+cooler) gives you a different result. Also, Is the PSU brand new? You might want to see if a replacement(donor) PSU changes your experience.

 

[Kenzoassasin]

You may want to see if breadboarding the system with the bare minimum(meaning one stick of ram, only boot drive and CPU+cooler) gives you a different result. Also, Is the PSU brand new? You might want to see if a replacement(donor) PSU changes your experience.

If I only use cpu, cooler, 1 stick ram and boot drive. The vga led is lit. 2700x doesn't have gpu in it.
The PSU is brand new. Already got rid of old one. A bit hard to find donor during this pandemic