Problem: mouse pointer doesn't move between displays

My mouse pointer isn't moving between my screens the way it should. Maybe it's flying off the left side of my left monitor and onto the right side of my right monitor, or maybe it's disappearing altogether, or something similar.

Possible explanations and solutions

Windows display settings may have been changed due to device reset/reimage, or swapping out of monitors, or recabling during summer, etc. See Configure Windows Display Settings.