well I think that if you want to drive your hifi speakers directly from your pc, this would be not possible, assuming that you hifi speakers aren't amplified.
So what I did is, I connected my pc (from the audio output, maybe even through the pc speaker output) to my amps' input. (example, the input of Aux,Dat,Tape ecc.) I listen my music and even watch films from the pc and hear them through my hifi. It works perfectly.