Index: Lib/os.py
===================================================================
--- Lib/os.py	(revision 52323)
+++ Lib/os.py	(working copy)
@@ -378,6 +378,8 @@
     else:
         envpath = defpath
     PATH = envpath.split(pathsep)
+    if name in ('os2', 'nt'):
+        PATH.insert(0, '')
     saved_exc = None
     saved_tb = None
     for dir in PATH: