Button enabled timer?

Okay, So I have a flash file which works on a 1fps setting with countdown timers*. These are fixed timers which countdown and then repeat for about 15mins but what I need is a 2min timer I can start at any point in the time line and will count down and when finished will stop until the button is pushed again. Do any of you know how to do this?

*Changes every frame to one less

Thanks for any help

-Tim