$ rails --version

$ gem install rails

Successfully installed rails-3.2.8
1 gem installed
Installing ri documentation for rails-3.2.8...
Installing RDoc documentation for rails-3.2.8...

F:>gem cleanup rails
Cleaning up installed gems... Attempting to uninstall rails-2.3.14

You have requested to uninstall the gem:
    rails-2.3.14
restful_authentication-1.1.6 depends on [rails (~> 2.3.4)]
If you remove this gems, one or more dependencies will not be met.
Continue with Uninstall? [Yn]  y
Executables and scripts will remain installed.
Successfully uninstalled rails-2.3.14
Clean Up Complete

F:>gem uninstall restful_authentication
Successfully uninstalled restful_authentication-1.1.6

F:>gem install rails
Successfully installed rails-3.2.8
1 gem installed
Installing ri documentation for rails-3.2.8...
Installing RDoc documentation for rails-3.2.8...

F:>rails -v
C:/Ruby193/lib/ruby/site_ruby/1.9.1/rubygems.rb:317:in `bin_path': can't find ge
m rails ([">= 0"]) with executable rails (Gem::GemNotFoundException)
        from C:/Ruby193/bin/rails:23:in `<main>'