I didn't know documents can get corrupted. The article you mention was very
interesting (though scary because it means my document can get corrupted
again).
Thanks for letting me know about this.

To reply to your question:
What kind of spaces are you referring to? How did you manage to delete
them?

I clicked on "view header and footer", then I clicked inside the footer
area, I used the arrows to go to the bottom of the area and then I used the
delete button to erase a few lines. (I don't know how those "lines" got
there, maybe because of the corruption, because I had never typed them in
myself).