Python won't open .py in cmd, problems with pip and a lot of oddities, what to do?

Question

Windows

I use cmd as a python compiler, and there is such a dilemma, I write a well-known command into a string, let's say python index.py, and I get "Python" in response, that is, the string simply does not see the python, or something like that. Yes, I move the disks in a row to the place where the code itself is, nothing changes. As far as I remember, a partial solution was to access all disks, some kind of flag for the command or something like that, I hope you understand the essence, I don’t remember the command that solved this problem, and it’s not the point. I was advised to remove the python from the computer completely, but this does not work for me either, the installer gives an error when uninstalling, when restoring the same thing. I assume that the problem is that I installed python several times, on all disks, which is probably what caused the problem.