We are a commune of inquiring, skeptical, politically centrist, capitalist, anglophile, traditionalist New England Yankee humans, humanoids, and animals with many interests beyond and above politics. Each of us has had a high-school education (or GED), but all had ADD so didn't pay attention very well, especially the dogs. Each one of us does "try my best to be just like I am," and none of us enjoys working for others, including for Maggie, from whom we receive neither a nickel nor a dime. Freedom from nags, cranks, government, do-gooders, control-freaks and idiots is all that we ask for.
Interesting computer problem today. Every indication of a hard drive failure. Replaced hard drive after a quick run to Staples ($189.). Same problem after reloading drive from external drive. Computer expert thinks it must be a motherboard problem. Then he says "Hmm, I've never seen a BIOS problem in 20 years but let's try asking BIOS to heal itself, just for the heck of it."
Instantly repaired. "Holy f-," says he. "This is a first for me: BIOS never fails."
Agreed, it's pretty rare. Did you watch what he did, in case it happens again? He probably pressed the Del key or F10 to get into the BIOS (Basic Input/Output System) right after the machine was turned on, then one of the F keys to restore the system defaults.
In looking for a cause, it's possible the BIOS chip overheated (some motherboards even have small fans on top of the BIOS chip to keep it cool), but I'd suspect the BIOS battery if the rig's a few years old. They're easy to replace. It's a nickel-sized "watch battery" and usually lies flat on the motherboard. Stick a tiny screwdriver down against the little tang and it'll pop right out. Replace it at the computer store and pop the new one in. You'll have to re-set your system clock & date after bootup.
And, looking on the bright side, at least now you have a spare hard drive at the ready.