Guess, you have to download LW again and install it; it will try to remove any previous version installed while installing itself. You can download it from here:
http://www.limewire.com/
Then you can go to START>Programs>Limewire>Uninstall.
Do not use the Add/ Remove Programs function of the Control Panel to remove LW.
By the way, any specific reason why you want to remove LW?? I'm just curious.