<?php

$user = "test";
$password = "test";

// Includes
include('../inc/config.inc.php');
include('inc/links.inc.php');

// -- Passwort abfrage ----------------------------------------------

if(!isset($usr) or $usr!=$user) {

echo "
<table width=\"303\" border=\"0\" cellspacing=\"1\" cellpadding=\"0\" height=\"169\" bgcolor=\"#336699\" align=\"center\">
 <tr>
  <td bgcolor=\"#336699\" height=\"110\">
   <table width=\"311\" border=\"0\" cellspacing=\"1\" cellpadding=\"0\" bgcolor=\"#FFFFFF\" height=\"136\">
    <tr>
     <td height=\"175\">
      <div align=\"center\">
	<form name=\"form1\" method=\"post\" action=\"$PHP_SELF\">
         <font face=\"Verdana, Arial, Helvetica, sans-serif\">
         <font size=\"2\">Name:</font>$br
         <input type=\"text\" name=\"usr\">

	 <font size=\"2\">Passwort:</font>$br
         <input type=\"password\" name=\"passwd\">

         <input type=\"submit\" name=\"Submit\" value=\"Login\">
        </font></div>
      </form>
    </td>
    </tr>
   </table>
  </td>
 </tr>
</table>";

// -- Passwort prufung ----------------------------------------------
}elseif ($usr==$user){
if($passwd==$password){

// -- Passwort richtig ----------------------------------------------
echo "
<link rel=\"stylesheet\" type=\"text/css\" href=\"$style\">
<table class=\"schrift\" border=\"0\" width=\"100%\">
  <tr class=\"l\">
    <td>
	A<span style=\"font-variant: small-caps\">dmin</span>
	I<span style=\"font-variant: small-caps\">nterface</span>
	$br
    </td>
  </tr>
  <tr class=\"m\">
    <td>
	<a href=\"index.php?section=link1\">Link1</a>
	<a href=\"index.php?section=link2\">Link2</a>
	$br
    </td>
  </tr>
  <tr class=\"m\">
    <td> ";

//-- Link Include ---------------------------------------------------

if(isset($_GET['section']) AND isset($dateien[$_GET['section']])) {
include $dateien[$_GET['section']];
}

//-------------------------------------------------------------------

echo "
    </td>
  </tr>
</table> ";

}
else {

// -- Passwort falsch ----------------------------------------------
	echo "<center>
		
		 <font color=\"red\">ZUGRIFF FEHLGESCHLAGEN !</font>
		
		

		<a href=\"#\" onclick=\"javascript:history.back()\">zurück</a>
	      </center>";
     }
}

?>

blaba 

if(isset($_GET['section']) AND isset($dateien[$_GET['section']])) {
include $dateien[$_GET['section']];
}

<?php
session_start ();
  if (!session_is_registered ("logged_in"))
  {
   $logged_in = 0;
   session_register ("logged_in");
  }

  if (!strcmp($user, "user") && !strcmp($pass, "password"))
   $logged_in = 1;

  if ($logout)
   $logged_in = 0;

  if ($logged_in) 
   echo "logged in. <A href=\"index.php?logout=1\">log out</A>";
  else
   echo "<FORM action=index.php method=get>User: <INPUT type=text name=user>
Password: <INPUT type=text name=pass>
<INPUT type=submit></FORM>";
?>

	session_start();

	$loggedin=($_SESSION['li'])?true:false;

	if (!$loggedin) {

		if (empty($_POST['loginformsent']))
		{
			// Loginformular
			//
			// wichtig: <input type="hidden" name="loginformsent" value="1">
		} else {
			
			// Prüfung ob $uname && $passwd richtig sind...
		
			// if (beidesok) { 		
			
			$_SESSION['li']=true;
		}

	} else {

		// Eingeloggt
		// 
		// zum ausloggen einfach session_destroy(); verwenden
	}

  session_start();
   $admin=$_GET['admin'];
   $pw="123";
   $usr="test";

if($admin=="login" and $_POST['pass']==$pw and $_POST['usr']==$usr){
      $_SESSION['pw']=$pw; $_SESSION['usr']=$usr; header("Location:?admin=in");
   }

   if($_SESSION['pw']==$pw and $_SESSION['usr']==$usr){
      echo "<a href=\"?admin=logout\">logout</a>

";

       //Seiteninhalt

   if($admin=="logout"){session_destroy(); header("Location:?");}
   }

else{

   if($admin=="login" and $_POST['pass']!=$pw and $_POST['usr']!=$usr){ 
    echo "<center><font color=\"red\">ZUGRIFF VERWEIGERT !!</font></center>"; }

  echo "<center><form action=\"?admin=login\" method=\"post\">";
  echo "Name:$br<input type=\"text\" name=\"usr\"> 
$br";
  echo "Passwort:$br<input type=\"password\" name=\"pass\"> ";
  echo "

<input type=\"submit\" value=\"Login\"></form></center>";
}