diff -r 5ea81e4c58a7 Lib/test/test_sys.py
--- a/Lib/test/test_sys.py	Mon Oct 17 20:44:22 2011 +0200
+++ b/Lib/test/test_sys.py	Mon Oct 17 23:47:24 2011 +0200
@@ -520,6 +520,13 @@
         self.assertTrue(repr(sys.flags))
         self.assertEqual(len(sys.flags), len(attrs))
 
+    def test_sys_flags_no_instantiation(self):
+        flags_type = type(sys.flags)
+        with self.assertRaises(TypeError):
+            flags_type()
+        with self.assertRaises(TypeError):
+            flags_type.__new__(flags_type)
+
     def test_clear_type_cache(self):
         sys._clear_type_cache()
 
diff -r 5ea81e4c58a7 Python/sysmodule.c
--- a/Python/sysmodule.c	Mon Oct 17 20:44:22 2011 +0200
+++ b/Python/sysmodule.c	Mon Oct 17 23:47:24 2011 +0200
@@ -1471,6 +1471,7 @@
 {
     PyObject *m, *v, *sysdict;
     char *s;
+    int res;
 
     m = PyModule_Create(&sysmodule);
     if (m == NULL)
@@ -1589,6 +1590,9 @@
     /* prevent user from creating new instances */
     VersionInfoType.tp_init = NULL;
     VersionInfoType.tp_new = NULL;
+    res = PyDict_DelItemString(VersionInfoType.tp_dict, "__new__");
+    if (res < 0 && PyErr_ExceptionMatches(PyExc_KeyError))
+        PyErr_Clear();
 
     /* flags */
     if (FlagsType.tp_name == 0)
@@ -1597,7 +1601,9 @@
     /* prevent user from creating new instances */
     FlagsType.tp_init = NULL;
     FlagsType.tp_new = NULL;
-
+    res = PyDict_DelItemString(FlagsType.tp_dict, "__new__");
+    if (res < 0 && PyErr_ExceptionMatches(PyExc_KeyError))
+        PyErr_Clear();
 
 #if defined(MS_WINDOWS)
     /* getwindowsversion */
@@ -1606,6 +1612,9 @@
     /* prevent user from creating new instances */
     WindowsVersionType.tp_init = NULL;
     WindowsVersionType.tp_new = NULL;
+    res = PyDict_DelItemString(WindowsVersionType.tp_dict, "__new__");
+    if (res < 0 && PyErr_ExceptionMatches(PyExc_KeyError))
+        PyErr_Clear();
 #endif
 
     /* float repr style: 0.03 (short) vs 0.029999999999999999 (legacy) */