Question Random and continued PC failure

[electronbluetwo]

I opened a desktop I built to change a fan on the video card, but when I went to boot it, nothing happened. If I jump the power connector over the 4 & 5 pins, I get mobo lights, fans, and the hard drives spin, but there’s no signal going to the monitor and the usb mouse doesn’t light up. I bought a replacement motherboard, which I installed today, and it behaves exactly the same. What would cause this?

 

[Ralston18]

More information needed:

Update your post to include full system hardware specs and OS information.

Motherboard? PSU? Case?

What/where are those 4 & 5 pins being jumpered?