Sorry for the delay, but first my computer stopped talking to outside devices, like the screen and keyboard, then I had to prepare for a trip and Christmas at the same time. I'm not sure I'm doing either one well, but they'll both be done after a fashion.
We're not sure what's wrong with the computer, but it works as long as there's nothing plugged into its rear USB ports. So my USB hub and external hard drive are both unplugged.
I feel a little guilty about this. It could definitely have been handled more quickly and with less disruption. On the other hand, I feel rather pleased that I've gotten into enough of a habit of posting that I really miss it when it's disrupted.