setcookie doesnt appear in explorer

hi every body i have write this simple cookie in two project in t he first one it works fine i use it in another project but when i click F12 i see nothing in the cookie i make debug i see it take values but it doesnt appear in explorer or churom .....

this is my code can i find help for my problem

function checkLogin($u, $p)

{

global $seed;

if (!valid_username($u) || !valid_password($p) || !user_exists($u))

{

return false;

}

$query = sprintf("

SELECT `U_id ' ,'Md5_id`, `M_Username`, `M_password`,`user_level` FROM `members`

WHERE

M_Username = '%s' AND M_password = '%s'

AND M_status = 'on'

LIMIT 1;", mysql_real_escape_string($u), mysql_real_escape_string(sha1($p . $seed)));

$result = mysql_query($query);

if (mysql_num_rows($result) != 1)

{

return false;

} else

{

$row = mysql_fetch_array($result);

session_start();

session_regenerate_id (true);

$user_md5id=$row['Md5_id'];

$_SESSION['loginid']= $row['U_id'];

$_SESSION['username'] = $u;

$_SESSION['ckey'] = GenKey();

$_SESSION['user_level'] = $row['user_level'];

$_SESSION['HTTP_USER_AGENT'] = md5($_SERVER['HTTP_USER_AGENT']);

$stamp = time();

$ckey = GenKey();

$on_offline="on";

$serial = trim(str_replace("(","",str_replace(")","",GetVolumeLabel("c"))));

$db = new mysqli('localhost', 'root', '', 'blabla');

$query=sprintf("UPDATE `login_case` SET `ckey`='$ckey',`ctime`='$stamp',`on_offline`='$on_offline',`Logindate`='$stamp',`hard_serial`='$serial' WHERE `U_id`='$user_md5id'");

mysqli_query($db,$query);

define("COOKIE_TIME_OUT", 10); //specify cookie timeout in days (default is 10 days)

define('SALT_LENGTH', 9); // salt for password

if(isset($_POST['remember'])){

setcookie("loginid", $_SESSION['loginid'], time()+60*60*24*COOKIE_TIME_OUT, "/");

setcookie("user_key", sha1($ckey), time()+60*60*24*COOKIE_TIME_OUT, "/");

setcookie("username",$_SESSION['username'], time()+60*60*24*COOKIE_TIME_OUT, "/");

}

return true;

}

return false;

}