Which page? Which download? Did you initiate a download from that page?

Separate Issue; Update your Shockwave Flash v15.0.0.152 http://get.adobe.com/shockwave/

Are you loading a web page (what is the address) or are you downloading something ?

in a previous version of firefox there was a means of stopping a long page downloading ( say it had video content ) if it turned out to be not what I wanted.

 I can't find the stop button in the latest version,  I am on a broadband limit, so this is why I want to stop it downloading.

Thanking you all for your help in advance

Okay, you are trying to load a web page. In or near the address bar, there should be a X. Pressing it should stop the page from loading more.

Flash block {web link} Never be annoyed by a Flash animation again! Blocks Flash so it won't get in your way, but if you want to see it, just click on it