python 기존 설치에 다른버전 설치시 에러 해결방법

관리자로 해도 

there is a problem with this windows installer package 라는 에러가 나옴

pip를 빼고 설치할것

After some looking online I found (here) that the issue was related to conflicting pip installs (I have a version already installed for Python 2.7 and apparently this is not compatible with the version that ships with Python 3.4.

To get around this issue I simply de-selected pip from the install options shown below and the install went ahead smoothly: