"Visual Editor" not working

Hey guys, just so you all know I have already tried the basics:
-Reverting back to default themes
-Disabling all plug-ins
-Updated to version 3.2.1 (was that version originally)
-Tried re-installing manually
-Tried re-installing online through WordPress
-Clearing cache
-Different browsers
-Different PCs
-Ensuring all files have at least permission 744

I think it may be something to do with my host’s settings (I’m using HostMonster) as I’m running the exact same thing on my localhost running through WAMP and there’s not a problem.
However I don’t know how WordPress works well enough to know why on Earth the host I’m using might be a problem with the Visual Editor?

Anyhow I’ll try and describe the problem a bit more specifically than the title:
When the Editor loads, the Visual tab is open, but the Editor itself (menu and font and HTML) looks as if it’s under the HTML tab. If I click on the HTML tab, everything looks like it should. Now if I click back on the Visual tab the menu disappears – leaving me with just the text box and the tabs to swap between.

I am well and truly stumped on this, and short of hacking WordPress to use a different editor (which I really want to avoid) – I have no idea where to even start.

Any help at all would be greatly appreciated, thanks.