Non-interactive installation of an additional Python environment on a computer which already has Python installed

I'm working on a deployment tool which will build a python environment with a number of dependancies pre-installed. According to the documentation on Python's web-site I should be able to do something like this:

msiexec.exe /i python_installer\开发者_运维百科python-2.4.4.msi TARGETDIR=c:\temp\install\fooX

However in the case where that version of Python is already installed on the system (in the regular C:\Python24 location) this command-line will attempt to repair the existing installation. It will not create a new installation in the TARGETDIR.

Does anybody know of additional command-line arguments which will help me achieve the following:

• I want the installation to block until the installation is complete. That way I can start the next process of my environment build once the current process has ended.
• I want the installation to always install to the TARGETDIR regardless of whether a valid Python installation exists elsewhere.

FYI, I'm using Python 2.4.4 on Windows XP 32bit.

UPDATE1: We have a solution to the "awlays installing problem", I just need a way to make the program block until completed. If I do /qn the process spawns a background process and terminates immediatly. I've always wondered why so many Windows tools work this way - it makes command line scripting impossible!

You could try the /a instead of /i flag:

From msiexec help:

/a <Product.msi>
    Administrative install - Installs a product on the network

Another option to consider is /qn:

/q[n|b|r|f]
    Sets user interface level
    n - No UI

You can get to the help window of msiexec by executing only msiexec without parameters.