How to install RVM on Windows 7

No RVM for you! From RVM’s FAQ:

Does RVM work on windows? Will it in the future?

NO. If you would like to manage multiple versions of ruby on windows please use pik which is an excellent tool by Gordon Thiesfeld. You can find it on GitHub. There are plans to include windows support in RVM 2.0.

Pik is an RVM for windows pik is a tool to manage multiple versions of ruby on Windows. It can be used from the Windows command line (cmd.exe), Windows PowerShell, or Git Bash. follow this link pik on windows