Try deleting LW's preferences folder when LW's properly closed. See point 3 here.
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.
And in case you're using Vista...
LimeWire Pref Folder in Vista
Which version of
Java are you using? Some people have had trouble with the latest
Java updates. Try this version instead. Use the JRE offline
installer & remove your current
Java version before
installing this one (it's easy enough to reinstall a later
Java if it turns out that
Java's the problem).
Archive: Download Java 2 Platform Standard Edition (J2SE) 5.0 Update 11
If that doesn't help, try reinstalling the latest version of LW (4.14.8) & make sure to use the offline
installer (when you click to download LW & the download box pops up, cancel that & you'll see the option to use the offline
installer).
Lime Wire » Download LimeWire
If all that fails

, right click on the LW desktop icon > properties > compatibility & run in compatibility mode for Win 2000 or NT, if you're using Win XP. If you're using Vista, try compatibility mode for XP.