Basic Sound Problem

I am having a problem with playing sound in flash, actually i have a main file say (a.swf) and in it a sound is playing, then when another movie is loaded by LoadMovie say b.swf (which also has its own sound) both the sounds play. And when i stop the sound in the main file and load the movie again the sound does not play. Can anybody help on this ???

Actually [COLOR=blue](can this be done, then HOW ???)[/COLOR]
[COLOR=black]I want the main movie to play its own sound and when I load another movie inside the main movie then I want to play the loaded movie’s sound and when i close the loaded movie then the sound of the main file to be played. [/COLOR]

Can anyone give a hint on this , plzzzzzzzzzzzzz.

My Logic : Will [COLOR=blue]onClipevent (load) { } and onClipEvent (unload)[/COLOR] { } [COLOR=black]work on this ??? when I load another movie on empty movie clip …[/COLOR]