Please Help

[ydg]

Just tried, and unfortunately this is what I get:

python : The term 'python' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the
spelling of the name, or if a path was included, verify that the path is correct and try again.
At line:1 char:1
+ python app.py
+ ~~~~~~
+ CategoryInfo : ObjectNotFound: (python:String) [], CommandNotFoundException
+ FullyQualifiedErrorId : CommandNotFoundException