[tlug] New Hardware Problem

[CL <az.4tlug@example.com>]

Trying to diagnose repeated total hardware shutdown after running about 
40~45 minutes.  Happens repeatedly and I can't seem to find any good 
reason for it.  Maybe someone here can think of something else to try.
I replaced a number of items with brand-name parts following an 
unexplained death of my previous box on New Year's Day.
- Case (Corsair brand), mobo (ASUS brand full ATX), CPU (AMD FX 8-core) 
/ CPU fan, and power supply (80 Grade) are all new.
- Memory (16Gb of Elixir brand DDR3 1600 -- 8Gb x 2), Nvidia HDMI video 
card (fanless Zotac w/4Gb onboard), HDDs (2 x 1Tb; 1 x Samsung 3.5 + 1x 
Toshiba 2.5 for backup), and 1 x ASUS DVD RAM/ROM drive are from the old 
box.
- Running Debian Jessie + WIN 10 in a virtualbox

- Both old and new machines use Realtek audio chips and it _appears_ as 
though the drivers are the same for both configurations.
- Motherboard configuration can see and describe both 8Gb memory 
modules, but says I have only 8Gb of memory installed.
Problem: After about 40~45 minutes of use, machine suddenly goes dead -- 
no power anywhere.  Restarts immediately and runs fine for about another 
40~45 minutes.  Does not appear to be temperature or power related.  
Machine is powered off a power strip and I have checked the output 
voltage of the socket and it is a flat 100~102V.
When left running overnight, it stayed on throughout the night 
unattended.  Today is a different story and I am trying to write a 
report.  Have set automatic backup to 5 minutes for my sanity.