Why does a preloader take as long to load 2nd time around

I’ve created a flash site (http://www.chrisdye.co.uk/home2) with links to swfs in seperate html pages, but when i go back to a page that has already loaded once i.e. the homepage, the preloader takes just as long to load the second time. I thought it should be quicker the second time round as it is stored in the computers cache?

I found a similar post ‘only load preloader once’ but didn’t really understand the solution:

[COLOR=RoyalBlue]assign a variable to check if something is loaded already. For example[/COLOR]

[COLOR=RoyalBlue] var clicked = false;

button.OnRelease = function() {
if(clicked){
//do nothing
}
else{
//load preloader.
//do other stuff.
[/COLOR] [COLOR=RoyalBlue]var clicked = true;
}
}
[/COLOR]
How is this different from the preloader AS ‘if bytes loaded’ Could anyone shed some light on what to do please…