hi im not an expert at this, but i have a solution that might work for you, i got it from one of the limewire developers team. search for a folder "Application Data"(usually in C:/Documents And Settings/user name/Application data)
in which u will find a folder of limewire. delete that folder completely, but before you do that make sure you have exited LW and that the tray icon has disappeared. then try installing LW again.
hope this works for u