Hi Oscar,

First thing to try is: Delete LW's preferences folder when LW's properly closed. See point 3 here & also point 2 if you've used older versions of LW in the past (there could be a folder in either location).
Fixes for LimeWire
This will kill all of your settings within options, you'll have to go back through afterwards & reset things. If you're not sure of your settings, go through LW's tools > options & write them all down, so that you can reset things later.

What version of Java are you using? People have had problems with Java 1.6.0_01 & _02. Try this version instead. Use the JRE offline installer & remove your current Java version(s) before you install this one.
Archive: Download Java 2 Platform Standard Edition (J2SE) 5.0 Update 11

If that doesn't help, you're going to have to give us some details. You've told us absolutely nothing about your system. We don't even know what OS you're using. So people have to guess how to help you & that's a PITA
System details - help us to help you -> Provide these details when you post!!!