First of all, what might seem an unrelated issue, but I believe it's related.
We had a lot of rain here last night, with more expected tonight. It's currently in the low 80s, although with the high humidity, it seems much hotter than that.
Yesterday, Saturday, when it started getting hot and humid--hours before the rains started--I began having problems with the mouse on this computer. I'd move the mouse, but it was excruciatingly difficult for the arrow on the screen to move, too.
I inspected the wiring, and found that, as usual, the insulated wires connecting all things are criss-crossed over each other on the table, touching each other.
When I took the wiring for the mouse (connecting it to the "tower") and draped it over the monitor, so it wasn't in contact with other wires, the mouse worked (works) fine, no problem at all.
Would the heat, humidity, and wires crossing each other, be the culprit here?
It's dreadfully hot and damp out here in the Sandhills, and there's no air-conditioning because the house is ancient and leaks like a sieve.