The box shut-completely-down (once); no errors listed (Event Viewer or Problem Reports).

The subject line says is all. The main focus (for me), to find some documented evidence (log), that this event happened. To be clear, both 'Event Viewer' and 'Reliability History\Problem Reports' --has absolutely no entries about any power and/or hardware issues since the last refresh. Also, after booting, the battery was at eighty-nine percent, with the power-adapter still connected to both a live A/C-outlet and the box.

I don't know where-else to look. From this point forward, I'll be running Sysinternals\ProcDump, approx two or three weeks later, b) reset the motherboard per the OEMs' directions; in that order. If I reset the board first, it may resolve the issue long enough for me to not get a clue. I only have thirty-days before the retailers return policy expires, then I'll have to file for an RMA;be without a machine.

Third machine, second replacement of the exact make/model for various reasons, not associated with 'this' behavior of shutting-down --without documented evidence. This machine runs most/more stable with: 1) the OEM\Preloaded OS and the drivers provided via the OEMs regional web-site; this machine does not connect to the Inet.

I am truly listening ...

Event ID 41: This event indicates that Windows restarted without a complete shutdown. Event ID 1074: This event is logged when an application is responsible for the system shutdown or restart.

I'm sorry, but I really don't understand your post. I assume this is a laptop since you refer to battery percentage.

Your first laptop shut down unexpectedly. You returned it for a replacement.

second laptop -What was your reason for returning this one? Was it same shut down issue?

third laptop -Now you're on your second replacement. You say "for various reasons not associated with 'this' behavior of shutting-down. This machine runs most/more stable ".
What reasons? You want documented evidence of WHAT?

@glasskuter -- In short, where else can/might evidence be found about this shutdown? I've already confirmed --the areas where the normal entries, e.g. event id: 41 and the like, are not found/listed for this instance.

Now I am REALLY confused...or crazy. You said the shutdown occurred on your first laptop. Now you are on your third laptop. If you returned the laptop that had the problem, any information regarding the shutdown would be on a laptop you no longer have.

If the original laptop is still in your possession, the only place to look would be event viewer for all events at the exact date/time the shutdown occurred. It will not necessarily say the word 'power.' As Freebooter said , software could have triggered a critical event or the shutdown could be caused by failing hardware. If it's hardware an event may not even have been created. The event viewer is a vast amount of information. There is no way anyone can tell you exactly what to look for in event viewer.

Now, reverting to a blue or black screen without loss of power is different. Data is stored in log files that can be gathered using the instructions here BSOD - Posting Instructions

IMO, a single shutdown would not have warrented returning the laptop. Flukes are not uncommon. If it happened again, then one would want to troubleshoot hardware by stress testing, monitoring temperatures, and testing ram and drive. A defective power supply can also cause such an issue.

If it only happened once it may not be a problem to worry about. If your return time is getting close to being expired and you think it's going to happen again I would go ahead and return it.

@glasskuter -- you are confusing yourself by twisting the words I clearly typed. Please review the original text; slowly.

@Winuser -- I only need assistance with finding any documented evidence of this shutdown. There has been one previous shutdown and it was logged; this one wasn't.