i need help on loggin account limit

[muntago Richard]

Good day everyone, This code updates or counts the number of times users logged in. I want to disable or make users login account invalid on 4th attempt by loading an error page such that the user will be ask to get new account. how do I proceed. Below is my attempt so far. Do i need to set count <=4 to true? or false?. If possible,how
thanks

<?
      if( !isset($_SESSION) ) { session_start(); }
	$database_db="cat";
	$user_db="root";
	$password_db="root";
	$host_db="localhost";
	$link=mysql_connect($host_db,$user_db,$password_db) or die ("couldnot connect: ".mysql_error());
	mysql_select_db($database_db, $link)  or exit('Error Selecting database: '.mysql_error()); ;
	$userid=$_POST["userid"];
	$password=$_POST["password"];
	$errormessage = "";
	$sql="SELECT * FROM usertab  where userid='$userid' and password='$password'";
      $sql1="UPDATE usertab SET count = count + 1 WHERE userid = '$userid'";
      $result1=mysql_query($sql1);

	$result = mysql_query($sql, $link)  or exit('$sql failed: '.mysql_error()); 
	$num_rows  = mysql_num_rows($result);
	if($num_rows==0 AND count <= 4){
		echo "error <BR>";
} 
else {
		header("Location: insert1.php");
		exit;
	}
?>

[Paul Clapham]

Look at it this way: when count is equal to 1, that means the user has made only one login attempt so far, right? So now consider what your code would do when count is equal to 1. Is that what you would want it to do?

[muntago Richard]

No my intention was to allow each user to login only 4 times and on 5th login attempt let it display an error message that their login credential is no longer valid meaning that they should get new username and password.
Thanks