Try delete LW's preferences folder when LW's properly closed. See point 3 here & also point 2 if you've used very old versions of LW in the past (there could be a folder in either location).
Fixes for LimeWire

This will change all of your settings within tools > 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.
Vista users: LimeWire Pref Folder in Vista