Since you're posting in the OSX forum, I'm assuming you do indeed have OSX, right (I could, be wrong)? Well then, select one of these files and press Command-I. From there, click the little triangle to the right of "Open With" try changing the default opening application.
Ah, but before you do that, check if it is indeed an mp3 file (if that is indeed it's extension)

__________________
iMac G4 OSX 10.3.9
RAM 256MB
LW 4.10.5 Basic
ADSL anything from 3 to 8Mbps/around 1024kbps

"Raise your can of Beer on high
And seal your fate forever
Our best years have passed us by
The Golden Age Of Leather"
-Blue Öyster Cult-