All pages constantly transferring data from server.

Hello,

All of the pages on my site are loading properly, but they constantly say "transferring data from [my site url]". The "loading" symbol on the tab in Firefox does not disappear, and the cursor has a loading thingy next to it (sorry I can't put this in more technical terms!).

This did not happen a little while ago - since then I've cleared the cache, rebuilt the theme registry several times and done some other modification of content. Edit - I also changed some imagecache preset settings and flushed some presets.

Tried using fiddler (HTTP debugger) to see if anything was wrong, I'm no expert at this sort of thing but the status codes I was receiving was a 200 (OK) and a whole bunch of 304s, which is fine, I think.

Can anyone suggest why this is happening?

Thank you.