Linux is a opensource platform. Most popular linux based operating system is ubuntu. The latest version of ubuntu is choose Ubuntu 12.10. The ubuntu 12.10 version contains latest features but it has long term support. The stable and LTS one is Ubuntu 12.O4 LTS.Ubuntu giving more preference to its secuirity so all root access is password protected. The command for gaining password protection is
root command:sudo,nautilus
eg: wivix@wivix:~$ sudo nautilus