Does this session script strong enough?

hi,

i have a session script, before i use it in my website, i want to know if this script is strong enough or have any bugs/weakness in it.
1. if so, please modify it, and make it stronger & give some explaination about it.
2. How to include cookie protection in this script

---------------------------------------
<?PHP
if (!isset($_SESSION["username"]) || !isset($_SESSION["password"]))
{
header ("location:index.php");
}
else
{
$username=$_SESSION["username"];
$password=$_SESSION["password"];

if(!$username || !$password)
{
header ("location:index.php");
}
else
{
include "delConfig/config.php";
$connection=mysql_connect($host,$user,$pass) or die(mysql_error());
mysql_select_db($db,$connection);

$loginQuery=mysql_query("select * from adminSp where adminUsername='$username' and adminPassword='$password'",$connection) or die (mysql_error());
$loginRow=mysql_num_rows($loginQuery);

if($loginRow=="0")
{
$_SESSION=array();
session_destroy();
header ("location:index.php");
}
}
}
?>

------------------

Best Regards

 

It's good pratice to store passwords hashed (md5 or sha1).

 

Hmm... why yor are started new tread, is there not enough informative? xttp://forums.digitalpoint.com/showthread.php?t=613906

 

i'm really sorry, it posted twice just because my very bad connection yesterday, i clicked it twice when the first time has no response. i hope administrator can delete this thread...