I've no idea where this tune is from (though I have heard it used as mood music in documentaries, and as background music in the last 'Biggest Loser UK') and I've never heard more than the first few bars, which are just a drum and high-hat. Then a guitar starts playing one note.
If 'bom' = the drum, 'tsh' = the high-hat and 'dow' = the guitar and full stops = the beat, it goes like: bom . . .tsh . . .bobom . . .tsh . . .bom . . .tsh . . .bobom . . .tsh then over that the guitar starts quietly going dowdowdowdowdowdowdow etc . Then it usually fades out as someone begins speaking. It sounds to me like it should be in the soundtrack of 'Trainspotting' or something equally dark.
If anyone can even make a suggestion, you'll make an old man very happy!