Thanks again Major Payne, the resources you gave me must have helped spark something in my mind. There were lots of little problems, but the main one (the one that caused the footer to float up...
Also, interestingly, when I view the website on my home computer as "file:///var/www/positivepaws/index.html" it renders correctly. If I look at it as "localhost/positivepaws/index.html" it errs in...
I have a problem. My website (downstay.net) has suddenly broke in IE and in Chrome (but it's still OK in firefox). The pages are not rendering correctly and I think it's a CSS problem but not sure....