‘php.exe’ is not recognized as an internal or external command, operable program or batch file

Question

‘php.exe’ is not recognized as an internal or external command, operable program or batch file.

Why does that error occur even though

Answer 1

Set PHP as environment variable from System as below to run it from CMD

1)Windows key + Pause
2)Click on Advanced system settings
3)Now click on Environment Variables.. button  
4)In system variable section search for Path and edit it as D:\wamp\bin\php\php5.3.13;(If one needs to append it to some already exits value then start path with;)
5)Now open CMD and run command PHP from any path where you don’t have PHP installed , in my case it’s C drive.
6)We can check above set Path from CMD using Path command also.