Wordpress Admin Buttons/Dropdowns etc not working

This is a very strange issue - I have two Wordpress blogs that both have this issue. When I log into wp-admin, the dropdown menus (for example: screen options and help) don't do anything when clicked. The side panel menu doesn't bring up the options for each heading unless clicked (so no mouseover) and if I go into a page or something similar, the buttons inside the edit won't work (add media etc).

The Support Chat here told me to ask the community as this is a very strange issue that doesn't seem to have an answer as of yet.

If anybody could help that would be great! We have tried disabling all the plugins and this did nothing.