Starise
If...a big if, you can find the disk that came with the mobo, you could attempt to reload bios from that.

That's a great idea, and I do have the disk. But... the version on the disk is a year older than what my motherboard is working with. I must have been able to update once in the past (2012, it seems), but that's as far as it went.
 
I've uncovered the reason for reboots, and that was needless Wacom apps for browser usage. Uninstalling them eliminated that problem. Still have a hit and miss relationship with the extra hard-drive. Most often I just wiggle the cables (powered down, of course) and it appears.
 
Yesterday I bit the bullet and ordered a new mobo/processor/ram setup. Welcome to the age of 3.9Ghz i5 and DDR4. The sense of adventure is about to increase.

I always try to do everything possible to save a setup if possible and this is why I was pulling at straws...but yeah, sounds like you made a good call there.
 
I would feel bad if you hadn't exhausted all of the possibilities first.