M-Audio Revo 7.1 Problem: Crackling Sound when Browsing

Here is my case:

Early observation:
I listened to mp3 file (burned from CD by myself) using foobar2000, then browsing the internet using Firefox. Whenever FF loads images, suddenly the sound is distorted (produce crackling sound). Sometimes the music is not sounded at all without clear reason, but the playback is not interrupted..

Later:
I found that the "interference" is not mp3 player specific, so using other software: WinAmp (5.3), iTunes (7.x), WMP (11), are no difference. Also I observed that playing muted *.wmv using WMP 11, and then listening to *.mp3 using other software, will provide similar crackling.

The problem is so annoying, for I cannot capture DV video+audio completely without frame drops and sound crackling/stopping.

Somebody can help?? Thank you in advance.

My Spec:
Board: Asus P5LD2-VM DH
Pentium D-805
2 GB RAM
Asus ATi X1600 Silent, video card
Firewire 800 (patched, so now able to run at its full speed))

OS: WinXP SP2

hell yeahh .. they never update the driver since Feb 2004.
Or, does the 1028_sf is actually updated regularly just as its USB Transit, but using the same name?

[off course that's stupid Q if being asked here ]