Can't view edit.php or post-new.php!

I cannot view edit.php (though for some reason works fine for ?post_type=page), and thus cannot post anything!

I disabled all my plugins, which allowed me to view the list of posts, and after clicking on one, to view the title – but not the editor.

All I see is the greyish background. I tried reinstalling 3.8, to no difference.

If I view the page source, there appears to be no </head> tag, and nothing that looks like it should be anywhere but the head. Seems like a WP bug, but I don’t know why it’s (seemingly) only affecting me. If this is a known issue, apologies, I haven’t seen anything on it – please point me to the appropriate thread.

I’ve had no other problems with the backend, and site (including all posts) displays fine.

Any help?!