Erased paragraphs

[Anne]

This has happened to me much too often. I am hoping someone knows what I must
be doing and can tell me how to disable that feature.
I am typing an email using word as email editor. I am not exactly sure which
key I hit in error, but I think I am using my right pinky trying to either
hit enter or shift, but I hit some other letter and it erases the entire last
paragraph. On occasion, I have been able to use undo, but most of the time
not.

 

[Anne]

I just did it again and I know now what I am doing. I hold the shift key with
my left pinky and hit the arrow up key with my right pinky by accident
instead of the question mark. That highlights the entire text and leaves it
in typeover mode. When I hit the next letter, it erases the entire
highlighted area.
In the options I unchecked "typing replaces selection" and I think that this
will stop this.
Yes, I know, the two keys are so far apart, how could I do this? I am not
sure, that is why it took me so long to figure this out. And, of course, it
is always just after you post the question.