Error on installing IE9: The latest version is installed

My computer has Core 2 processor with 2GB DDR2 RAM and Windows Vista 32-Bit installed on it. I am getting problem with the installation of Internet Explorer 9. I have installed it from the internet but the installation was not completed. When I am trying to re-install it I am getting an error message which says, the latest version is installed. But the Internet Explorer 9 is not displaying in the Programs and Features. So I am not able to uninstall it. When I have turned off the internet Explorer my PC was working properly. What is to be done? Can I wait for the update window or I have to install it again? But how can I do it? Please help me to get out of this problem. I will thankful for all help.
