Intalll RoR on Windows XP, NOT connected to Web

I have installed Ruby and RubyGems, latest versions from
rubyonrails.com, successfully after downloading zip files.

Attempting to install rails with > gem install rails
gives a message that the computer [not connected to the web for
security reasons] attempts to find a file.

Can anyone point me to the location of the rails download and
alternate instructions on installation?

TIA