Strange sound in WMP6.4

[paull2k]

Hey can someone tell me what might possibly be causing this strange problem? Whenever I play just about any mp3 file in WMP6.4 I can sometimes hear a faint knocking sound in the background, this does not happen with any of my other programs, such as Winamp3, RealONE, or any others, just WMP6.4. I also have WMP9 RC1 and that does not have any problems with playing any other types of media. I highly doubt it's anything to do with my system, but here are the specs for it anyway:
Pentium 4 @ 2.0 GHz;
256 DDR RAM;
DVD-Rom: 16x;
CD-RW Drive: 40x10x40x;
Sound Blaster Audigy Card (with updated drivers);
GeForce4 MX 420 64mb (Getting a new one, unfortunately I've had many problems with getting it )
if anyone can give me any help or advice with this problem I would greatly appreciate it. Thank you.

[paull2k]

I have no clue what could have fixed that problem. All I did was update RealONE Player so it could play certain file types, and just minutes ago, I found that it doesn't make that weird knocking sound anymore. I don't know why it would have fixed it, but I ain't gonna question it, it stopped!

[kugmo]

must be the devil.

[Milennium]

I have the same problem, could be a bad codec.
Not fixed, anyone a idea?