Same symptoms from two different machines doesn't sound like a manufacturing problem, though a quick search for owner reviews did turn up one unlucky buyer who went through several machines with different quality control problems.
G-CPTN, I know you said cooling vents are clear, but just to check, does that include the inlets? I ask because for a while my HP laptop would cut out after half an hour of heavy CPU work, in my case on reboot the BIOS flagged up overheating as the cause: the air inlets are on the base of the machine, and it normally rests on a tabletop when in use. The base is raised slightly by 4 rubber pads, but not enough to give sufficient airflow when the machine is very busy. Keeping the back edge half a cm off the surface solved the problem.
Caveat, I am no Windows expert, most of the time including now my PC runs under Linux, but if anything is being logged, you can display it using the event viewer admin utility. (Probably findable under 'control panels', or type 'event Viewer' into the Start search-box.) Info will be under 'Windows Logs', I'd guess most likely under Setup or System.
Good luck.
WGW