sound card woes --cracks between songs

Hi all ..
I am having a sound card issue and was wondering if anyone could assist me ..I have an m-audio revolution 7.1 ..It snaps and cracks between songs whether playing mp3's or an audio cd.

here are my system specs
amd athlon xp + 2200
256 ddr ram
windows xp service pack 1
Am dropping another 256 ram in tonite ..

I have the latest drivers for the card as well as the latest direct x --still doing it ..
M-audio tech support is rather run around and has been of no help in the last 2 and half weeks -- My first issue with this card was lockups of the system so I upgraded to the specs I mentioned above ..Now this issue --I think there is something wrong with the card ..Also it does not matter waht speakers you use ,have treid pc set up ,home set up as well as a ghetto blaster --the snaps are still there ...

Apperciate any insight one might have