Could you try to back your current system
PATH and remove from that list a path to Anaconda's Python. Then, please
C:\PlatformIO\penv folder and restart Atom. It will install private Python2.7 into
C:\PlatformIO\python27 and will use it for PIO Core calls and will not conflict with Anaconda's pre-compiled Python.
So, after that, you can return back Anaconda's Python into the system
P.S: Anaconda doesn't install a clean version of Python interpreter. They have own pre-built versions...