Really odd issue with eqtheme.mp3

[Neiv]

x = EQ Theme
y = New Theme
z = Old EQ Theme

I have changed out my eqtheme.mp3 (x) (in the Everquest folder) to a different intro music clip (y) (named the same as the old). Hence, when I start up EQ, it now plays the new theme music (y). I'm using an xp machine.

However, when I load this same clip onto my Vista machine, it continues to play the EQ theme (x) rather than the new music (y).

That's not the oddest part. When I simply double click the new eqtheme.mp3 file, it opens Windows Media Player and plays the EQ theme (x). But when I rename the file (to, say, eqtheme1.mp3) and doubleclick it, it opens Windows Media Player and plays the new music (y). When I rename it back to eqtheme.mp3, it again defaults to the EQ theme music (x).

When I delete the file altogether and open EQ, it still plays the EQ theme music (x) on the Vista machine, but plays the old original EQ music (z) on the xp machine.

Anyone know what the heck is going on?