Index: modules/system/system.admin.inc
===================================================================
RCS file: /cvs/drupal/drupal/modules/system/system.admin.inc,v
retrieving revision 1.95
diff -u -p -r1.95 system.admin.inc
--- modules/system/system.admin.inc	9 Oct 2008 00:02:29 -0000	1.95
+++ modules/system/system.admin.inc	10 Oct 2008 19:27:21 -0000
@@ -645,7 +645,7 @@ function system_modules($form_state = ar
     $extra = array();
     // If the module is requried, set it to be so.
     if (in_array($filename, $modules_required)) {
-      $extra['required'] = TRUE;
+      continue;
     }
     $extra['enabled'] = (bool) $module->status;
     // If this module has dependencies, add them to the array.
@@ -689,7 +689,6 @@ function system_modules($form_state = ar
       '#type' => 'fieldset',
       '#title' => t($package),
       '#collapsible' => TRUE,
-      '#access' => ($package != 'Core - required'),
       '#theme' => 'system_modules_fieldset',
       '#header' => array(
         array('data' => t('Enabled'), 'class' => 'checkbox'),
@@ -722,7 +721,6 @@ function system_sort_modules_by_info_nam
 function _system_modules_build_row($info, $extra) {
   // Add in the defaults.
   $extra += array(
-    'required' => FALSE,
     'dependencies' => array(),
     'dependents' => array(),
     'disabled' => FALSE,
@@ -773,7 +771,6 @@ function _system_modules_build_row($info
     $form['enable'] = array(
       '#type' => 'checkbox',
       '#title' => t('Enable'),
-      '#required' => $extra['required'],
       '#default_value' => $extra['enabled'],
     );
     if ($extra['disabled']) {
Index: modules/system/system.test
===================================================================
RCS file: /cvs/drupal/drupal/modules/system/system.test,v
retrieving revision 1.12
diff -u -p -r1.12 system.test
--- modules/system/system.test	15 Sep 2008 20:48:09 -0000	1.12
+++ modules/system/system.test	10 Oct 2008 19:27:22 -0000
@@ -89,6 +89,18 @@ class EnableDisableCoreTestCase extends 
   }
 
   /**
+   * Assert that core required modules cannot be disabled.
+   */
+  function testDisableRequired() {
+    $required_modules = drupal_required_modules();
+    foreach($required_modules as $module) {
+      // Check to make sure the checkbox for required module is not found.
+      $this->drupalGet('admin/build/modules');
+      $this->assertNoFieldByName('modules[Core][' . $module . '][enable]');
+    }
+  }
+
+  /**
    * Assert tables that begin with the specified base table name.
    *
    * @param string $base_table Begginning of table name to look for.