how to remove login script, need help please

Hi,

i wondering if someone can help me to remove login script,
the script look like:

if(@$_COOKIE['admincp'] == md5($admin_username.$admin_password)){
    if(@$_GET['p'] == 'logout'){
        logout();
    }else{
        html_interface();
    }
}else{
    if(@$_POST['login'] == $admin_username && @$_POST['password'] == $admin_password){

        setcookie('admincp', md5($admin_username.$admin_password), time()+3600, '/', false);

        //reload
        echo '<meta http-equiv=refresh content=0;URL=?>';
    }else{
        html_login();
    }
}

function contents(){

    $page_request = @$_GET['p'];

    switch($page_request){
        case 'pages' : pages(); break;
        case 'comments' : comments(); break;
        case 'thumbnails' : thumbnails(); break;
        default : homepage(); break;
    }

} 

PHP:

because i want to change the login authentication, but my page will be blank

 

html_interface();




function contents(){

$page_request = @$_GET['p'];

switch($page_request){
case 'pages' : pages(); break;
case 'comments' : comments(); break;
case 'thumbnails' : thumbnails(); break;
default : homepage(); break;
}

}



Try above code.