Hi Cali,

if you do not need to use the installer, you can have several ruby 
installations on your PC at the same time. Just unzip the package and put 
it somewhere. In cmd.exe do

SET PATH=F:\myruby\bin;%PATH

to put the ruby binary into PATH. That's all. When you need to run ruby 
scripts by double clicking on them you need to set this path system wide 
or user wide in windows controls / system. Or you just type explorer in 
cmd.exe, which then inherits the environment of your current cmd.exe.

When I remember right, the zips may come without rubygems or with an old 
versions of rubygems (depends on the ruby version). Then just download 
the latest rubygems zipfile, unzip it and run the setup script. Then you 
can install gems.

So you can easily switch ruby versions. The ruby binary knows where it 
actually lives and uses all the directories, which belongs to its setup 
automatically without any setup in registry etc. So just using the full 
path to the ruby.exe is enough to choose the ruby version you want. This 
is interesting, when you eg. want to run a mongrel as a service in 
windows. In cmd.exe it is better to modify PATH, so you it will be enough 
to just type ruby.exe.

It even works on UNC-paths over a network. Only cmd.exe does not allow a 
cd to an unc-path. I therefor prefer 4nt over cmd.exe. 

Handling open source apps this way works for a huge number of software 
like perl, python, ruby, php, apache, mysql, postgresql, sqlite, gimp, 
inkscape etc. I have about 100 different packages on my PC installed this 
way and I am working with many of them at work every day since many 
years. So my conclusion is: Installers sucks - they really do, since they 
dramatically limit your choices. But this does not work with all 
software. Most commercial software is limited to installers.

If you need more Information just ask or better send me an email. I have 
some experience on running those apps on windows and if you are a command 
line junky like me, for 4NT I even have a set of startup scripts, which 
makes those things even more easier.

Regards
Thomas