login screen and floating windows gone!

Several of the WordPress sites I host for family and friends have lost the format of their login screens

see http://midwifediaries.com/wp-login.php for an example.

They have also don’t load up the floating screen seen when previewing a theme, adding a photo to a post and looking at the ‘details’ of a plugin.

I’m totally stumped guys, one of the sites is a fresh install of WP all updated and without any plugins whatsoever and it still has these same issues.

at the same time my oldest site http://www.cyclefar.com in the root directory of my site is fine