Song from 2006 to 2007, h2o?

So several years ago, i think it was 2006 or 2007, in Europe, on the music channel, there was this great song, all i could remember from it was a good beat to the song, in the vid there was a black girl singing, and wearing like school girl clothes. The song kept having "h2o" in it. Like h-2o, - being a beat in between. I need someone's help fast because i cant get this song outta my head without playing it through. Thanks