It's a file, you should be able to find  it with file search. If it's hidden,
just ensure that you are looking for hidden  files.

Or if you're seeing it in a file open  or file save dialogue, then right-click
and choose the delete  option.

Not sure how you know there are two personal  workbooks if you can't see them.
Give us a bit more info and we'll think about how to delete it.