Why does XML not display in browser but correctly does in XML Notepad 2007 (Microsoft)?

I am coding in XML with an XSL attached.

When I open this in browsers (IE + Google Chrome) it displays a white screen. However when I open the same files in XML Notepad 2007 it displays the XML data with the correct styling from the XSL.

Am I missing something about displaying it browsers?

I have the standard declarations at the top and I can't see anything odd about my code; it's a very simple file I'm testing on to try and get it working.