Movie Clip Mess! FLA incl

Hi guys,

I hope you can help.
I’m trying to work with movie clips as buttons here but am getting very frustrated because I don’t know where to really look for help in terms of google search terms.
I have a movie clip button which has some activity whilst it is rolled over. I want this mc button to load 2nd movie clip inside it.
At the moment the second movie clip is loading automatically (only want it to load when first mc button is hovered over) and 2nd mc disappears when hovered over. I need to be able to hover over 2nd mc as there are buttons on it!
Perhaps I am going about this in totally the wrong way but please let me know so I can move on.

Here is the FLA file
http://newmedia.leeds.ac.uk/ug06/cs06ek/work/test.fla.zip
PLEASE HELP! Forever grateful