It appears that NetBeans and Aptana/RadRails are the most common adopted IDE's for Ruby on Rails development, but both needs the Java Runtime Environment to run.
I'm looking for an IDE wich doesn't need JRE to run. If it is lightweight and installs very fast would be better, because I will be programming in computers with old hardware and Windows XP.
Do you know any? Thanks a lot.
Komodo Edit is one of the best IDEs I've ever used, and it has Rails support (although maybe not as good as Aptana/RadRails). If you have money to spare, I'd highly recommend Komodo IDE, as it has some great extra features, but if not, Komodo Edit has everything you need. As for speed, it's slow to start up but after that it's as fast as any other "lightweight" editor you've used.
What about the editor that comes with ruby-one-click for windows? Would it work? (the one written in ruby).
There is also gvim or vim if you are feeling adventurous.
Actually I would say that Vim paired with rails.vim is amongst the most popular editors for Rails. Vim, gVim and Cream are all available for Windows.
Learning curve is massively steep, but its worth it.
Also, if you are doing any serious Rails work, development on Windows sucks. It takes way too long to spin up a script/console or a web. Tooling is much better on Linux. When I'm doing Rails work on my Windows box I do it on an Ubuntu VM.
I did not use this program, but "System Requirements" did not indicate requirements for Java Runtime Environment in Windows version.