=== modified file 'includes/session.inc'
--- includes/session.inc	2007-08-12 15:55:35 +0000
+++ includes/session.inc	2007-09-23 08:11:11 +0000
@@ -48,6 +48,7 @@ function sess_read($key) {
   else  {
     $session = isset($user->session) ? $user->session : '';
     $user = drupal_anonymous_user($session);
+    setcookie('drupal_login_check', TRUE, time() + 31536000, '/');
   }
 
   return $user->session;

=== modified file 'modules/user/user.module'
--- modules/user/user.module	2007-09-19 18:00:52 +0000
+++ modules/user/user.module	2007-09-23 09:21:48 +0000
@@ -878,6 +878,13 @@ function user_menu() {
     'type' => MENU_LOCAL_TASK,
     'file' => 'user.pages.inc',
   );
+  $items['user/no_cookie'] = array(
+    'title' => 'Cookie problems',
+    'page callback' => 'user_no_cookie',
+    'access callback' => TRUE,
+    'type' => MENU_CALLBACK,
+    'file' => 'user.pages.inc',
+  );
   $items['user/reset/%/%/%'] = array(
     'title' => 'Reset password',
     'page callback' => 'drupal_get_form',
@@ -1226,7 +1233,7 @@ function user_authenticate($name, $pass)
 }
 
 /**
- * A validate handler on the login form. Update user's login timestamp, fire
+ * A submit handler on the login form. Update user's login timestamp, fire
  * hook_user('login), and generate new session ID.
  */
 function user_login_submit($form, &$form_state) {
@@ -1241,7 +1248,10 @@ function user_login_submit($form, &$form
 
     sess_regenerate();
     $form_state['redirect'] = 'user/'. $user->uid;
-    return;
+  }
+  if (!isset($_COOKIE['drupal_login_check'])) {
+    unset($_REQUEST['destination']);
+    drupal_goto('user/no_cookie');
   }
 }
 

=== modified file 'modules/user/user.pages.inc'
--- modules/user/user.pages.inc	2007-09-10 13:14:38 +0000
+++ modules/user/user.pages.inc	2007-09-23 09:42:56 +0000
@@ -363,3 +363,8 @@ function user_page() {
     return drupal_get_form('user_login');
   }
 }
+
+function user_no_cookie() {
+  $text = t('Seems your browser does not accept cookies.');
+  return $text;
+}