hi mike,
to get the original signal out of your pc go via usb to an external hifi dac with 24-bit/192khz and from there optical to the digital input of your receiver. this way you bypass the soundcard entirely. works for music and movies. you can also use the analog rca outs of the dac. they cost only abt $200-$300 and the improvement is dramatic.
here is a link for the korean styleaudio dac, but that's for australia. just google for usb dacs in the usa.
http://www.soundreference.com.au/
yogi