Powerless by Nelly Furtado
The chord sequence is
D Em G D
[ Tab from: http://www.guitartabs.cc/tabs/f/furtado_nelly/powerless_crd.html ]
repeated throughout the song, for verse and chorus.
It's not one of the all-time most suited to acoustic guitar songs,
but I find it works quite well if I strum it with my fingers,
occasionally slapping the body for rhythm.
D : xx0232
G : 320033
It also sounds alright if you throw a capo on one of the higher frets,
and arpeggiate the chords to mimic the banjo sound.