Disks can get "bad blocks" over time. CHKDSK /r will identify those blocks as unusable, quarant them off, and move any data in them to healthy blocks (if possible). Sounds to me like you need to do this, before any data in them is irrevocably lost.
Well, I'm embarrassed and I am offering an apology. I have an external hard drive I leave connected to the laptop and File History is backed up to that. I also use the external storage device to backup our business financial software records. The disk errors reference Hard Disk 1, and in checking my storage management, I see that my computer is calling this external hard drive Hard Disk 1. My internal drive is Hard Disk 0. I powered down the laptop and disconnected the drive, then powered the laptop up and checked Event Viewer. No disk errors listed.
I think I do need to be concerned about the health of the external drive, but that's an easy replacement.
Thanks for your advice and patience, Simrick. I've learned a lot here. I'll mark this thread 'solved', with a huge sigh of relief. And I think I should replace that external hard drive.