sub score {
    ## however you decide to assign a score to a filename
}

sub choose_weighted {
    ## from that other node
}

my @audio_files;
find(
    sub { /\.(mp3|wav|wma)$/ && push @audio_files, $File::Find::name },
    'C:\music'
);

## this could go inside the while loop if you needed to recalculate
## relative weights after every song is played:
my @weights = map { score($_) } @audio_files;

while (1) {
    my $index = choose_weighted(\@weights);

    system 'c:\Program Files\Windows Media Player\wmplayer.exe',
           $audio_files[$index];

    print "Another? ";
    last unless <STDIN> =~ /^y/i
}