Cursor sticks in upper left corner of screen in Word

[greggggggg]

Hi, All --

I use CTL+Home and CTL+End a lot to get around documents...or I used to
use them.

Now, after years of navigating with those shortcuts, they sometimes
cause my cursor to jump to the upper left corner of the screen and
stick there.

I can use my mouse to point somewhere else in the document...but it
doesn't matter. As soon as I release the mouse button, the cursor jumps
up to the upper left corner.

Any thoughts on how to remedy this?

Many thanks, Gregg