Windows 7 cracks

[Leonard_Pb]

Using Windows 7 Professional 32-bits,
ASUS P5Q SE PLUS Motherboard, Integrated VIA soundcard Version 6.0.1.7100,
Audacity 1.3.12-beta.
There is no problem in recording sounds from different audiostreams using ‘stereo mix’, but all the recorded music gives a hum, or better cracks, as if recording old LP’s. The volume of the crack keeps track with the volume of the music: volume lower crack lesser; louder sound louder crack. (The crack does not appear when using the built-in recorder in Screamer Radio or Real Player).
A common cause that I see on forums is ground hum or buzz, but that cannot be the cause here. When I use my older PC Windows XP on the same place, with all the cables and gear around, there is no crack or hum.
Has anyone an idea where I have to look at?
Thanks for helping.

[whomper]

are you sure you are not clipping?
google shows many people with similar problems with asus pcs.
those threads provide many possible solutions.
can't say if any of them will fix *your* problem or not.