Please completely uninstall the version which is there in your system. Prior to that do download the latest version & alos the previous version, so that in case the latest version is broken, than you can switch to the previous again.
You will find all the versions here:
http://www.videolan.org/vlc/download-windows.html
I have given the link for Windows XP. You can switch to the home page & get it for other versions as well.