Wht does my swf starts over again?

Hi ,
I’ve build a game and in the last frame I show the score and “Game over”. And the game should stop there and never start again (unless you open the game again). But somethimes it DOES start over again.

the code in this last frame is

score_total.text = "Your score is: " + score;

the weird thing is that it happens somethimes… and not every time.
Can somebody help me? What am I doing wrong?

ps. sorry if my english isnt that good. It’s not my native language