I have recently tried to install Python 3.4 as an alternative installation on my system in an attempt to familiarise myself before migrating code. My main Python installation is 2.7.6.
I tried the 64 bit installer for Windows, but it came up with an error message
There is a problem with this Windows Installer package. A program run as part of the setup did not finish as expected. Contact your support personnel or package vendor.
After this the install is rolled back (from the point shown below):
I have eventually found a solution to this posted below and decided to share in case anyone else was having the same issue.