The main WordPress window and top menu bar are no longer displaying when I log in to the Dashboard. The only thing that displays is the sidebar. The site itself appears to be working fine, but I can't edit or create new posts, or do anything. My ISP recently upgraded to PHP 5.3.28 to PHP 5.4.30 - I'm a pretty low-end computer user, so I don't know if that would make any difference or not. Does anyone know what might have caused this? Many thanks!