Can't run python after downloading script.

I am the newest of the newbs. Just learning how to navigate atom and python and I can't seem to test code in atom, so, I would like help. I ran a simple test
print('my name') and got the following errors:

Error 1 "'python' is not recognized as an internal or external command,
operable program or batch file.
'python' is not recognized as an internal or external command,
operable program or batch file.
[Finished in 0.063s]
[Finished in 0.066s]"

Error 2 "'python' is not recognized as an internal or external command,
operable program or batch file.
[Finished in 0.066s]
^C
^C"

I have python downloaded on my windows 7 pc, and I have the shell for practice, but it's a hassle going in an out of atom, which of course is far superior. Please help!