Hard Disk Platter crash update
It looks like I have no way of repartitioning that hard disk without attempting to access the 1st platter, so I'm left with a hard disk that can't boot at all, but still accessible as a scratch drive if I take care not to access the C & D drives.
I'm going to try to toss in a very old 10 GB drive I have and run the OS off it and see if that works.