The clock stopped again = Kello pysähtyi taas The clock has stopped again = Kello on taas pysähtynyt I sense a small difference in these two sentences. First one is a more current event and the second one is something that you notice at some point but not right away. But definitely so close that they can be alternative answers, especially if the Finnish frase is talking about the clock "seisoo". The word "seisoo" doesn't have alternative options when used in this context.
In German, clocks also "stand" once they have stopped, even modern ones. In English, you still say "roll/wind down the (car) window", also you usually do not roll/wind anything anymore, unless its an old car. I suspect that seisoa has just remained as the correct verb in Finnish. Thinking of a wind up clock is definitely a good way to remember (and likely the origin)!