System Won't Post After PSU Replaced


May 31, 2016
So, let's start from the beginning.

Here's the custom build I started with
Processor: Intel Core i7 6700k
Mobo: ASUS H170-PRO
Graphics: MSI GTX 970
Memory: 1x 8GB ADATA DDR4
Power: 500w ALLIED AL-D500EXP
120GB SSD boot drive and 1TB HDD

So I was wanting to add an Nvidia GTX 980 to the system to run along with the 970. (I realize this doesn't work in SLI, but I was using it for 3D rendering, which can make use of two different cards)

Anyway, so I knew I'd need to upgrade the PSU. So I got a Corsair CX750M 750w PSU. Some may say that's skimping, but I figured it's bronze certified, it should do.

So I got the PSU replaced and the card put in. I powered on my system, it started, all LED's and fans came on and then (poof?) everything turned off. Now, I get the LED indicator light on the mobo still coming on, but the system does not even start, let alone post. I've taken both GPUs out and the new PSU out and swapped it for the old one and I'm getting the same thing. That LED indicator is on, and if I plug Ethernet into the rear I/O, the port LED turns green as well. But neither the CPU/chassis fans nor the chassis LED's light up. I've made sure the 4/8 pin and the 20+4 pin connectors are secure, and the front panel pins are correct, I've reseated the RAM to different slots, as well.

Could it be that the front panel pins have shorted? Is that a thing? Or did I fry my system somehow with the PSU swap?

My main suspicion would be with the motherboard, but I just think it's weird that the Ethernet and standby LEDs would work if the motherboard is what going wrong. I don't think it's the CPU (although anything is possible) because I've had a CPU go kaput on me before, and at least the fans and LEDs still came on.

Any suggestions?

Thanks in advance.

EDIT: I just shorted the 750w and it powers the system fan just fine. So the issue has to be with either the Mobo or front panel inputs, right?