“Dell Dual Core 780”
There’s your problem. My son bought one of those for $15 at the university auction. It turned out to be one of my old work machines. PSU’s are suspect
I suspect it's the legacy BIOS boot sequence. I don't know what the problem actually was, as I have solid instances of Win 10 running on lesser and older machines than this. But, suffice to say, most users have machines older than three or four years, and don't utilize RAID/mirror arrays and on-call IT personnel. They have one box/laptop, and they should expect to be able to tun it on and do what they need to do without hassle. If Windows can't handle this, then it's time to finally wean myself off of Windows.