Is it this? http://www.youtube.com/watch?v=0d7ZBCFaiKU&feature=related
If not - I have no idea, but your description sounds a lot like Orbit's dance version of Barber's Adagio For Strings http://www.youtube.com/watch?v=SRqndwCqa5g
I have it on my iPod for when I'm going to gym. (not often!)