si ce l'ha ma si apre Quick Time.
Cmq ora ho modificato il codice e con Firefox funziona tutto alla grande mentre con IE la muscia non parte ne automaticamente ne premendo il tasto play di Windows Media.
Ecco il codice:

<OBJECT ID="NSPlay" WIDTH=281 HEIGHT=70 classid="CLSID:22D6F312-B0F6-11D0-94AB-0080C74C7E95" codebase="http://activex.microsoft.com/activex/controls/mplayer/en/nsmp2inf.cab#Version=5,1,52,701" type="application/x-oleobject">
<PARAM NAME="FileName" VALUE=""http://www.miosito/song.mp3">
<PARAM NAME="AutoSize" VALUE="0">
<PARAM NAME="AutoStart" VALUE="1">
<PARAM NAME="ClickToPlay" VALUE="0">
<PARAM NAME="DisplaySize" VALUE="0">
<PARAM NAME="EnableContextMenu" VALUE="1">
<PARAM NAME="EnableFullScreenControls" VALUE="0">
<PARAM NAME="EnableTracker" VALUE="1">
<PARAM NAME="Mute" VALUE="0">
<PARAM NAME="PlayCount" VALUE="1">
<PARAM NAME="ShowControls" VALUE="1">
<PARAM NAME="ShowAudioControls" VALUE="1">
<PARAM NAME="ShowDisplay" VALUE="0">
<PARAM NAME="ShowGotoBar" VALUE="0">
<PARAM NAME="ShowPositionControls" VALUE="0">
<PARAM NAME="ShowStatusBar" VALUE="1">
<PARAM NAME="ShowTracker" VALUE="1">
<!--
<PARAM NAME="ShowControls" VALUE="1">
<PARAM NAME="ShowDisplay" VALUE="0">
<PARAM NAME="ShowStatusBar" VALUE="1">
<PARAM NAME="AutoSize" VALUE="0">
<EMBED TYPE="application/x-mplayer2"
PLUGINSPAGE="http://microsoft.com/windows/mediaplayer/en/download/"
ID=NSPlay
Name="mp_905804870"
Width="281"
Height="70"
Src="http://www.miosito/song.mp3"
AutoSize="0"
AutoStart="1"
ClickToPlay="0"
DisplaySize="0"
EnableContextMenu="1"
EnableFullScreenControls="0"
EnableTracker="1"
Mute="0"
PlayCount="1"
ShowControls="1"
ShowAudioControls="1"
ShowDisplay="0"
ShowGotoBar="0"
ShowPositionControls="0"
ShowStatusBar="1"
ShowTracker="1"></EMBED>
</OBJECT>