Audio popping and crackling with Creative xMod

I bought some months ago a Creative xMod sound card. I've got a laptop with
Windows Vista Home Premium installed.



I hear some popping and crackling noise only when I watch video with Windows
Media Player. VLC is also affected by the same problem, but if I set the
video output to "Windows GDI" instead of "DirectX" the noise disappears.



There's no noise when I listen to music with Windows Media Player or when I
watch video or listen to music with Windows Media Center.



How can I solve this issue? I've tried reformatting PC and reinstalling
everything without success.