Cookies php

Bonjour,
J'ai un petit soucie de cookie ... a chaque foiis que je me logue mon scripte dois générer un cookie...
Mais celuici ne doi pas rester car on me demande de me re-identifier... on voi appeine la page entre les 2...
Voila un extraie du code...


//test to see if server is closed to logins
$playerfound = false;

$res = $db->Execute("SELECT * FROM $dbtables[ships] WHERE email='$email'");
if($res)
{
$playerfound = $res->RecordCount();
}
$playerinfo = $res->fields;

$lang=$playerinfo[lang];
if(empty($lang))
$lang=$default_lang;
SetCookie("lang",$lang,time()+(3600*24)*365,$gamepath,$gamedomain);
include("languages/$lang" . ".inc");

setcookie("interface", $mainfilename);

$userpass = $email."+".$pass;
SetCookie("userpass",$userpass,time()+(3600*24)*365,$gamepath,$gamedomain);

$banned = 0;
$res = $db->Execute("SELECT * FROM $dbtables[ip_bans] WHERE '$ip' LIKE ban_mask OR '$playerinfo[ip_address]' LIKE ban_mask");
if($res->RecordCount() != 0)
{
SetCookie("userpass","",0,$gamepath,$gamedomain);
SetCookie("userpass","",0); // Delete from default path as well.
setcookie("username","",0); // Legacy support, delete the old login cookies.
setcookie("password","",0); // Legacy support, delete the old login cookies.
setcookie("id","",0);
setcookie("res","",0);
$banned = 1;
}

if($server_closed)
{
$title=$l_login_sclosed;
include("header.php");
die($l_login_closed_message);
}

$title=$l_login_title2;
include("header.php");

bigtitle();

if($banned == 1)
{
echo "<center><p><font size=3 color=red>$l_login_banned<p></center>";
include("footer.php");
die();
}