YES! It is exactly what you assumed. 
 The default value is "C:\Python30\Python.exe", and  there is also another entry "path",its value is "C:\Python25\".

Does that mean I should not start python from the "Run" dialog box? 

非常感谢您的回复！> Subject: [issue4402] os.getenv('PATH') return different result between 2.5 and 3.0rc3> To: zhaolu8@hotmail.com> From: report@bugs.python.org> Date: Tue, 25 Nov 2008 08:24:21 +0000> > > Amaury Forgeot d'Arc <amauryfa@gmail.com> added the comment:> > Can you please check with the "regedit" application whether you have an> entry for the key:> > "HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\Windows\CURRENTVERSION\App> Paths\python.exe"> > (this key is used when you type "python" in the "Run" dialog box)> > What is its "(Default)" value?> Is there an additional entry named "PATH"?> > (I presume that (Default)=C:\Python30\Python.exe, and PATH=C:\Python25\)> > _______________________________________> Python tracker <report@bugs.python.org>> <http://bugs.python.org/issue4402>> _______________________________________
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