Stop/pause for slideshow

hey all,
ok so i have a simple setup
each frame on the main movie pulls in an external jpg. on entering that frame.

this movieclip ( slideshow timer) is associated with a play button.
frame 1 (slideshow timer)just has a stop.

once the play button is pressed then
the following code in
frame 2.(slideshow timer) begins to switch through the frames on the main movie.
but if i want to stop the slide show it doesn’t seem to do anything.

i suspect that a function cannot be removed but have not found anything to say whether it can or can’t.

[COLOR=Blue]function jumpFast(){
//Then call this function with the setInterval

setInterval( jumpFast, 7000);

// the playhead will jump to the n frame [/COLOR]

i tried an if …else … scenario but can’t get the code right.

any suggestions???