Please read the following & click on the 'fixes for LW' link:
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.

The folder isn't called 'preferences'...it's called .limewire, or LimeWire (depending on which location it's in).