Stopping a preloader in HTML

I’ve got an html document with two frames (main one on top and a small one with buttons for navigation on the bottom).

There are like 6 buttons. If I press button one, an html file loads that contains big flash document. It begins to preload in the main frame. I want to be able to press button two, interupting the preload, and load a new html document and flash file into the main frame, but it won’t do it until the preloader stops.

Is there a solution?