Weird behaviour from pycharm interpreter

Good evening everyone. 

I'm currently struggling to solve a problem with the additional modules I installed for python. 
I don't know why, but I cannot manage to add modules to python and make them work on pycharm. I recently installed curses, and it works fine when used using the interpreter, but won't work on pycharm, I keep getting the error message "module _curses not find" but it isn't the only problem. I recently installed matplotlib in the library root, and after a few tests it worked fine. But, as I started a new project recently, I couldn't import matplotlib without the code exiting with a ModuleNotFoundError. What I cannot explain is that my old test project for matplolib still works ! 

Even tough my old test project and my new project have the same paths in their interpreter, I cannot possibly import matplotlib in the latest, but still can use it in the test project I used to make sure matplotlib was correctly installed. Plus when I check the external libraries in my new project I can see matplotlib amongs them. 

I'm really not accustomed to pycharm, and might totally miss something, but after a lot of online research I do not understand why pycharm won't find a module that is installed in the library root... 

Here's an image of the path of the interpreter of my old test project : 

Here's an image of the path of the interpreter of a new project : 

And in my new project, I can see that matplotlib is in the libraries of the library root file.

Please pardon me if this is a simple problem I cannot solve due to my lack of experience. Any help is appreciated and I can give any additional informations is needed. Thanks a lot for your time and good night.