Here is one thread dealing with this issue to get you started. If it doesn't help then use the search option on forum. Words like 100% or CPU usage
http://www.gnutellaforums.com/showth...ght=100%25+CPU
This is usually caused by a bad Java Install, but not always.
If you can't find any answers post again. include all relevant info. Limewire and Java version etc.