First of all, I apologise for starting a thread about sessions. I did read through the troubleshooting guide, but I couldn't find a solution for my problem. I have written my own software for my club site, where members can login in to change their details and update photos. My software works 100% fine in Firefox, but in Internet Explorer it has issues when logging in, which is what I don't understand. It seemed to even work on Internet Explorer when I asked a couple people to try it when random club members had problems with it, and now it won't even work on IE on my machine (though I use Firefox normally so I didn't realise I had a problem). The login code is as follows: <?php // login.php session_start(); require_once('functions.php'); if (isset($_POST['UserName']) && isset($_POST['Passwd'])) { $UserName = $_POST['UserName']; // if the user has just tried to log in $Passwd = $_POST['Passwd']; $db_conn = db_connect(); if (!$db_conn) { // log them out if there's no database echo 'Could not connect to server database - please try again later.'; end_session(); } else { $query = 'SELECT * FROM members WHERE ffname="'.$UserName.'" AND pwd="'.$Passwd.'";'; $result = mysql_query($query, $db_conn); if ($result && (mysql_num_rows($result) == 1)) { // they are in the database so register the user id $_SESSION['valid_user'] = $UserName; if ($UserName == "zzedmin") header("Location:./admin.php"); else header("Location:./change.php"); } else header("Location:./logout.php"); } } if (!isset($_SESSION['valid_user'])) { ?> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head><title>European Ford Owners Club of Australia</title> <style type="text/css"> <!-- a:link {color:#FFFFFF} a:visited {color:#FFFFFF} a:hover {color:#FF0000} a:active {color:#FF0000} --> </style> </head> <body bgcolor="#647FC2" onLoad="document.thisForm.UserName.focus();"> <font face="Arial, Helvetica, sans-serif" size="3"> <font color="#993300"><h2>This area is reserved for members only <a href="view.php">Go Back</a></h2></font> <br> <h4>Please enter your Login Name and Password</h4> <form action="<?php $PHP_SELF ?>" method="post" name="thisForm"> <table border="0" cellpadding="2" cellspacing="2"> <tr> <td width="150" align="right">Login Name</td> <td width="250"><input type="text" name="UserName" size="25" maxlength="20"></td> </tr> <tr> <td align="right">Password</td> <td><input type="password" name="Passwd" size="10" maxlength="8"></td> </tr> <tr> <td align="right"> </td> <td align="right"><input type="submit" value="Log in"></td> </tr> </table></form> <?php } echo '</body></html>'; ?> Where do I start looking for a problem that doesn't appear in Firefox, but does in Internet Explorer? I'm reading up as many troubleshooting guides as I can to learn more about php, but feel like I am getting nowhere fast. Any help would be appreciated. Tim