This as been discussed several times bro...

There must be a software mixer 4 yer soundcard, somewhere in there u'll find the input level... some sondcards namelly SoundB do this thru a 2nd mixer view .. try clicking on the top left simbol of your mixer windows, there should b some option 2 view the record mixer or the input view or something similar.
I'm almost sure U'll find that the input level on the line in is low, so u'll need 2 turn it up!

PS - make sure u r using the line in and not the Mic In.

Z