Pycharm does not see standard modules, what should I do?

Question

Windows

available: Win10
pycharm 5.0.4 pro
python 3.5.1
problem: after installing new version of python(3.5.1) and uninstalling old(3.4) pycharm refuses to see standard python modules. all sorts of sys, os and others cannot be imported in the editor - it underlines in red. print() doesn't work - underlines in red and no autocompletion and stuff like that. At the same time, the run command or python console from the same pycharm are launched as they should, what is needed is imported, everything is ok. But the problem is in the editor. the interpreter is indicated, I don’t know where else to look, I need help

Answer 1

The problem was somewhere in the config , I just renamed (so as not to delete just in case) the config folder, and restarted paycharm. after starting the settings everything worked as it should.

Answer 2

In the project settings, specify the path to the new python

Answer 3

File → Settings → Project Interpreter
or
win → ubuntu → osx