Have you done a system check? Check your system over with your utilities & clean up your registry.

Also defragment your HDD. How much ram do you have? So you tried the Repair using add/remove control panel?

Last resort would be to try to install the international (multilingual) version of LW. I don't normally recommend this b/c it forces LW to use an almost obsolete version of Java. ALternatively try an older version: http://www9.limewire.com:82/download/

I hope you configured your firewalls to allow LW access: http://www.limewire.com/english/content/firewalls.shtml