A follow-up: I never found the answer to this and it just happened again. However, this time, I resisted doing ANYTHING in Word while the cursor/book thing was happening and instead killed time doing other things for 5-10 minutes or more. (Other times, I frantically tried to save open documents and switch between open files, etc., which seemed to overload Word and cause it to stop responding.)

My new "do-nothing" approach, on the other hand, seems to prevent the crash. After a while, I came back to Word and was able to again work in (and save) my open documents.

I'm still curious what the heck causes this--am I inadvertently hitting a shortcut key that runs some process that uses up resources? In any case, I thought others having this problem might benefit from this "solution," such as it is.

Sam