Change the Windows PATH environment variable

1. Can not edit the environment variable by system setting due to access right
Go to "Control Panel" => "System" => "Advanced System Setting", it is denied because my user doesn't have the right to edit it.

2. Change it by SETX command

C:\> setx PATH "%PATH%;d:\cygwin\;c:\python27"

3. Then open another command prompt, and use the set command to check

C:\>set PATH
Path=C:\Perl64\site\bin;C:\Perl64\bin;C:\Program Files (x86)\MiKTeX 2.9\miktex/b
in;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;d:\cygwin;c:\python27"