Php is not recognized as an internal or external command error solution

In this video you can see, how to fix this error - 'php' is not recognized as an internal or external command, operable program or batch file.

[pawekrawczyk]

I saw many videos, nothing worked. Thank you man, very helpful.

[marciajohnson]

My screen is just black where it says all those things that but I can't open it to my PC I can't do anything so how do I get it off the black screen

[shubhamkhule]

After adding path in environment variable it still showing this error. Please help me

[marciajohnson]

I cant open it. All i see is the black screen