Horizontal lines on some pages

I have some lines appear on 3 pages while designing it. I am not sure at what point they appeared as I did not notice till I published. On two of the pages that are the wider than longer pages, there is one horizontal line right in the middle of the page and on the home page, there is one horizontal line right at the top with the header. These lines are not clickable whatsoever. I've tried zooming in till they were an inch wide and I cannot select them, I cannot color them. I even went as far as drawing a white filled box over them and once I published the page again, they returned. I used a template page that had a grey background pasteboard with what looked to be leaf outlines on it. I changed the pasteboard to white. I did notice when I zoomed in that part of that grey line seemed to having what I believed to be a part of that pasteboard leaf etching. On the home page at the very top, it almost looks like it's attached to the top header line but it is not. On the "Instructor" page and the "scheduler" page it is right in the middle. The line is not on any of the other pages. I am out of ideas on how to fix it and any help would be appreciated. Thanks very much! Also, is there a way I can get the webpage to fix the viewers screen instead of having margins like it currently does?
Web address of the page is http://carolinaflightacademy.xara.hosting/

The lines are probably on the mouseover layer or the page background which is locked, you will need to unlock it prior to deleting the lines.

The lines were locked in the page background. Thank you so much!