diff -r 51ac5f06dd04 Lib/mimetypes.py
--- a/Lib/mimetypes.py	Tue Jul 24 03:45:39 2012 -0700
+++ b/Lib/mimetypes.py	Wed Jul 25 11:43:56 2012 +0900
@@ -238,30 +238,35 @@
         if not _winreg:
             return
 
-        def enum_types(mimedb):
+        def enum_types(hkcr):
             i = 0
             while True:
                 try:
-                    ctype = _winreg.EnumKey(mimedb, i)
+                    subkeyname = _winreg.EnumKey(hkcr, i)
                 except EnvironmentError:
                     break
                 else:
-                    yield ctype
+                    yield subkeyname
                 i += 1
 
-        with _winreg.OpenKey(_winreg.HKEY_CLASSES_ROOT,
-                             r'MIME\Database\Content Type') as mimedb:
-            for ctype in enum_types(mimedb):
-                try:
-                    with _winreg.OpenKey(mimedb, ctype) as key:
-                        suffix, datatype = _winreg.QueryValueEx(key,
-                                                                'Extension')
-                except EnvironmentError:
+        with _winreg.OpenKey(_winreg.HKEY_CLASSES_ROOT, '') as hkcr:
+            for subkeyname in enum_types(hkcr):
+                # Only check entries that begin with dots, 
+                # i.e. file extensions
+                if not subkeyname[0] == ".":
                     continue
-                if datatype != _winreg.REG_SZ:
-                    continue
-                self.add_type(ctype, suffix, strict)
-
+                # subkeyname is the file extension
+                with _winreg.OpenKey(hkcr, subkeyname) as subkey:
+                    try:
+                        mimetype, datatype = _winreg.QueryValueEx(
+                                                 subkey, 'Content Type')
+                    except EnvironmentError:
+                        # throws EnvironmentError if no 'Content Type' value
+                        continue
+                        
+                    if datatype != _winreg.REG_SZ:
+                        continue
+                    self.add_type(mimetype, subkeyname, strict)
 
 def guess_type(url, strict=True):
     """Guess the type of a file based on its URL.