ho seguito il tuo consiglio ho aperto un <div id ="layut"> a questo layut ho assegniato il layut e tutto il contenuto andra tra questo tag e il tag di chiusura comunque ho fatto cosi ma non riesco a spostarlo in centro
codice:
<?php
include_once ("includes/include.php");

$ip = $_SERVER['REMOTE_ADDR'];
$date = date('Y-m-d H:i:s'); 

?>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>Rcwebagency</title>
<script type="text/javascript" src="script-javascript/flashobject.js"></script>
<SCRIPT TYPE="text/javascript" SRC="script-javascript/content.js"></SCRIPT>
<script src="script-javascript/AC_RunActiveContent.js" type="text/javascript"></script>
<script type="text/javascript">
_uacct = "UA-312115-1";
</script>
<script type="text/JavaScript" src="popup.js"> </script>
<script type="text/JavaScript">
<!--
document.oncontextmenu = nocontextmenu; 
document.onmousedown = norightclick; 
if (window.Event) 
  document.captureEvents(Event.MOUSEUP); 

function norightclick(e) 
{ if (window.Event) 
  { if (e.which == 2 || e.which == 3) 
    { return false; } 
  } 
  else 
  { if (event.button == 2 || event.button == 3) 
    { event.cancelBubble = true 
      event.returnValue = false; 
      return false; 
    } 
  } 
} 
function nocontextmenu() 
{ event.cancelBubble = true 
  event.returnValue = false; 
  return false; 
} 
//-->
</script>
<meta http-equiv="content-type" content="text/html; charset=iso-8859-1">
<meta name="generator" content="HAPedit 3.0">

<link href="stil-css/rc.css" rel="stylesheet" type="text/css">
</head>
<body>


<div id="layut">   
 <div id="flahmenu"> 
        <div id="flashcontent"> 
          <div id="menu"> 
            

</p>
            

Welcome to RcwebAgency .

              We have detected that you do not have the Flash 6 player installed.

              Please Click Here
			  to download the Flash plugin.</p>
			  
            <p  class="style1">[img]immagini/player.gif[/img] 
          </div>
		  
          <script type="text/javascript">
		  	// <![CDATA[
			var fo = new FlashObject("flash/banner.swf", "Menu", "990", "350", "false", "");
			fo.addParam("quality", "high");
			fo.addParam("menu", "false");
			fo.write("menu");
				// ]]>
		</script>
	     </div>  
       </div> 
	 </div>   
</body>
</html>
e css cosi
codice:
[CODE


CODE] body{
	margin :0 auto;
	padding:0;



}
#layut {
	text-align: center;
	background-color: #EEE;
	border: 3px solid #DDD;
	height: 100%;
	overflow: hidden;
	width: 990px;

}
#flashcontent {
	font-family: Arial, Helvetica, sans-serif;
	font-size: 12px;
	font-weight: bold;
	color: #0099CC;
	text-align: center;
}
#menu {
	height: 350px;
	width: 100%;

}