--- a/mercurial/windows.py	Mon Feb 14 11:12:31 2011 +0100
+++ b/mercurial/windows.py	Mon Feb 14 11:12:35 2011 +0100
@@ -73,6 +73,38 @@
 def openhardlinks():
     return not _is_win_9x()
 
+_HKEY_LOCAL_MACHINE = 0x80000002L
+
+def system_rcpath_win32():
+    '''return default os-specific hgrc search path'''
+    rcpath = []
+    filename = executable_path()
+    # Use mercurial.ini found in directory with hg.exe
+    progrc = os.path.join(os.path.dirname(filename), 'mercurial.ini')
+    if os.path.isfile(progrc):
+        rcpath.append(progrc)
+        return rcpath
+    # Use hgrc.d found in directory with hg.exe
+    progrcd = os.path.join(os.path.dirname(filename), 'hgrc.d')
+    if os.path.isdir(progrcd):
+        for f, kind in osutil.listdir(progrcd):
+            if f.endswith('.rc'):
+                rcpath.append(os.path.join(progrcd, f))
+        return rcpath
+    # else look for a system rcpath in the registry
+    value = lookup_reg('SOFTWARE\\Mercurial', None, _HKEY_LOCAL_MACHINE)
+    if not isinstance(value, str) or not value:
+        return rcpath
+    value = value.replace('/', os.sep)
+    for p in value.split(os.pathsep):
+        if p.lower().endswith('mercurial.ini'):
+            rcpath.append(p)
+        elif os.path.isdir(p):
+            for f, kind in osutil.listdir(p):
+                if f.endswith('.rc'):
+                    rcpath.append(os.path.join(p, f))
+    return rcpath
+
 def system_rcpath():
     try:
         return system_rcpath_win32()