Hi - I was running into thick concrete walls when I was using 3.4.3 interpreter in that I was unable to install requisite packages like PyQt receiving errors telling me that there was no version that satisfied the requirement.
I upgraded from 14.04 to 16.04 (Ubuntu), installed the latest version of PyCharm Pro (2017.1.2) and updated my interpreter to use 3.5.2. Now, when I go to Settings -> Project Interpreter, I can see a list of the installed packages but when I go to add a new package, something trivial like "web", the package list comes up empty.
I read the other posts here about the similar problem but couldn't derive a solution because of either platform or version differences. I'm new to Python so you're going to have to use little words to explain to me why this is happening and how to fix it...