Community

Through a mouse click or a keyboard stroke, my cursor has changed to a
block instead of a single character.
Now when I put the cursor on a line of text, and hit the space bar to move the
text, it instead moves over and eraces the text.

Randy

You've probably already worked it out but you are in overwrite mode instead of insert mode. You can change back by pressing the "insert" key.

If you select View from the menu and ensure that "Status Bar" has a tick next to it, you will see some useful info at the bottom of the screen including Ovr which will indicate whether you are in overwrite mode or not.