WordPress not allowing me to create posts upon migration

Hi there

We have recently moved our WordPress site from host A to host B. The migration has went smoothly except for an issue where we cannot create any new content correctly, ie a post, user or page.

The following screenshot shows the WYSIWYG has disappeared once we click on “new post”. Custom fields remain.

http://imgur.com/a/cvrMx

We have tried replacing all wp-include and wp-admin files with a “fresh” copy directly from WordPress 3.7.5, plus other loose files in the wp directory but the problem still exists.

We have tried disabling all 25 plugins and reverting our theme to Twenty Twelve.

We have also tried repairing the database, but none of these options allowed us to post or create content.

Thanks in advance.