Ma ti posto come mi hai chiesto il codice della index( l'intera pagina cosi' magari sei piu' agevolato)
eccola:

<html>
<head>
<title>sito andrea</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<link rel=stylesheet href="stile.css" type="text/css">

</head>

<body bgcolor="black">
<script language="JavaScript">
<!--
// prelevato su http://www.web-link.it
if (navigator.appName == "Microsoft Internet Explorer"){
document.write('<BGSOUND SRC="m.mp3" LOOP=INFINITE>')}
else {
document.write('<EMBED src="m.mp3" WIDTH="0" HEIGHT="0" AUTOSTART="true" LOOP="false">')}
// -->
</script>

<table width="80%" border="0" align="center" valign="top" cellpadding="0" cellspacing="0">
<tr align="center" valign="top">
<td valign="top"colspan="2">
<span class="landrea2">
<? include("toppage.htm"); ?>
</span>
</td>
</tr>
<tr>
<td class="landrea">
<? include("sinistra.htm"); ?>

</td>
<td width="573" height="400"background="images/centrale.jpg">

<?php
$pagina=$_GET['pag'];

if ($pagina=="contatti"){
require('contatti.htm');
}
?>
</td>

</tr>
</table>


</p>
</body>
</html>