Ruby and Rails versions and path issues on Ubuntu OS

Please read the context : I've got a Ruby on Rails app that running on Heroku server and everything works well. The problem is that my local server don't work anymore (Note that I tried some updates (shell, …) and maybe one of them went wrong but i'm not sure and I'm not experimented enough to identify the issue). I have currently two major issues : - Rails command lines don't work anymore in my app (example : rails server, rake, bundle…). I think that the problem comes from the path, but again, not 100 % sure. Note that I tried to fix this issue myself and I try a new install of rails, but it doesn't work. - Ruby and Rails versions are different between desktop (ruby 1.9.3, rails 3.2.16) and my gemfile app (ruby 2.2.3, rails 4.2.3). Note that rvm doesn't work anymore. Im looking for a developer who can explain me how to fix these issues, so french or english speaking is required for this project. I think that the best way will be to share my screen but feel free to tell me if you have a better way.