Two other things I could think of causing this would be either a Security Program preventing LW from starting up, or a corrupted preference folder. Check all Security Programs on your system whether LW is added as exception. If you run Norton Security, delete all reference to LW in that program and then restart the program so that you have to newly allow LW.
As for the preference folder, read on how to delete it here in Point #2 & 3 in Fixes for Limewire
http://www.gnutellaforums.com/showth...threadid=36420 