Perhaps something hasn't been put back quite right - could you maybe check that it's been assembled correctly then submerge it in the tank up to the point of the water outlet arm (where the water gushes out), then turn it on (without your hands in the tank LOL) and see if it makes any noise. If you can hear a rumbling or humming sound then you should be able to get it working, try turning it off and giving it a shake in the water, turn on again and do that a few times to see if it will kick start it. Other than that, take it apart again and reassemble it.
If you're worried about doing this yourself you'll have to wait till your dad gets home to sort it out for you and show you how it's done. If it's not the actual filter it might be the fuse, like someone else said. But try to get it going by tonight if poss. Failing that, if nothing gets it going it'll mean a new filter (please, Dad, please LOL). The fish won't survive too long without a filter running as each day they produce a lot of waste = ammonia etc and with no filter bacteria to transform the bad chemicals into safe chems you know what that means...
Off home soon, so will check back tomorrow and see how you got on.
Nite nite - Athena
p.s. just one last thing - if it turns out you need a new filter, don't throw away your old filter sponge. Keep it and add it to your new filter (providing it fits - or cut a chunk off and fit it in the new filter - you need the good bacteria that's on the sponge)