How to have multiple versions of Ruby AND Rails, and their combinations on Windows?

Since Windows doesn't support rvm (Ruby version Manager), how do we have

• Ruby 1.8.7, Rails 2.3.8
• Ruby 1.8.7, Rails 3.0.0
• Ruby 1.9.2, Rails 3.0.0

on the same PC? Virtual machines can be used but it is kind of troublesome.