The song is made in A-minor. The song plays at 135 BPM. I assume that Tiësto has made those sounds with hardware or through sampling.
This is the bass:
It appears pretty early in the song and keeps going on until the end. As you can see the bass is really easy to make.
This is the melody:
So, I assume that the melody is recorded live. The melody appears somewhere in the middle of the song. And by the way if you have Sylenth1 you will have the preset named "Lethal Industry" which sounds like the melody of this song. So you won't have to sound design the melody.
Here you can listen to the song: