Computer enters strange unresponsive state when idle after motherboard replacement

Question

A few weeks ago I was playing a game on my PC when suddenly, I heard a screech typical of what you hear right before the power cuts out via my headphones. I thought that was the case. However, my PC still had full power but there was no output of any kind. No video output. No lights from either my keyboard or optical mouse no response. And my GPU fan started blowing intensely as if unregulated. I figured it was a motherboard issue after an unsuccessful restart after the incident.

So fast forward a week later. I've got the new mobo and have installed it. Things seem to be working fine. The PC starts up normally. I figure everything is fine so I leave it unattended. I come back and it's doing the same thing. No output, no response. I restart it again. Same thing.

It seems like it's entering the same state everytime it's supposed to idle. I've never encountered a problem like this. What's going on?

Comp Specs:

CPU: AMD Phenom II X4 945 Deneb Quad-Core

GPU: 2 x HIS IceQ 5 H577QT1GD Radeon HD 5770 Turbo 1GB 128-bit

PSU: APEVIA ICEBERG ATX-IB680W-BL 680W ATX12V / EPS12V SLI

MoBo: MSI 870A-G54 AM3 AMD 870

Answer 1

It seems like the mobo is being affected by the improper power supply. There are few cases where, the SMPS will be faulty and power supply to mobo is uneven causing IC failure in selective ICs like RAM IC. Consequently this results in NO POST Issue. If this is the case, then the only way to fix this is to check the mobo in authorized service center and replace the faulty ICs. Also replace your SMPS with a new one and then check whether the issue reoccurs or not.