Cannot install Windows Live Messenger?

Hello,

I've been having a few problems with Windows Live Messenger, it's updated and everything. So i decided to uninstall it and re-install. I search for it in the Add-Remove Programs and it wasn't listed? So i go thru the directory and delete it myself. I download the installer and it says i already have WLM when i clearly don't!
Can anyone suggest an un-installer or something?

thanks!