Initially, I have ruby 1.9.3
version installed in my windows 7 and i have installed ruby 2.0.0p195
recently and have tested from command promot (
The problem could be because you are behind proxy/firewall that blocks you from downloading from rubygems.org. See the below thread on rubygems.org for similiar issue:
http://help.rubygems.org/discussions/problems/799-ruby-gem-install-problems-on-windows-xp
Try using --http-proxy option while installing.
For people who are not able to make it work through --http-proxy, try the below. Added from the comment below.
gem install rails --http-proxy --source http://rubygems.org --debug -v