System Python conflict between Anaconda and existing Python installation

The solution is simply to uninstall python (for example, run the original python installer and select the uninstall option). The python key in the windows registry will be removed (which is what unregister means in this context).

Here is a link to a script that will unregister a Python installation (if you haven't come across it already). I personally have not dealt with anything like this. It seems like it should work, but you may have to tinker around with some of the paths in the script to get things to work. The links in @nightuser 's post will also probably fix the issue.

Why not just remove your version of Python? You could do a pip freeze > requirements.txt with your current Python and add them to Anaconda, or create an environment with Anaconda using those packages. Anaconda has greatly decreased the amount of time I spend setting things up.