Problems with expandable menus on Admin pages

I’ve been having problems with the expandable menus on my admin pages. They won’t expand if they’re collapsed and they won’t collapse if they’re open. Simple features within the open menus like check boxes and text fields are working just fine, but I can’t do things such as drag and drop widgets or add tags to posts. Oddly, the left hand main menu and the help feature are expanding, collapsing, and working just fine.

I’ve tried turning all of my plugins off and I’ve tried reinstalling WP. I’m out of ideas. Can anyone please help?