A rar file is a package....to unwrap it you must "unrar" it.
Use WinRar to unrar it....easiest program by far
YOU MUST CHOOSE THE RIGHT VERSION OF VISTA (32-bit is the simpler version of windows Vista with less features)
(32-bit Vista)
http://download.cnet.com/WinRAR-32-bit/3000-2250_4-10007677.html?tag=mncol
(64-bit Vista)
http://download.cnet.com/WinRAR-64-bit/3000-2250_4-10965579.html?tag=mncol