Your prefs will either be in C:\Documents and Settings\your name\Application Data\LimeWire (this is a hidden folder, so you'll have to show hidden files & folders to see it!
or (if you've been using an older version) it could be in C:\Documents and Settings\your name\.limewire
Go through tools > options in LW & make sure that you know what all your settings are.
Close LW & make sure it's really closed.
Delete the folder.
Now open LW again & go back through tools > options, reset your options the way you like them.
Give LW a while to settle down (say 1/2 hour) & see if it behaves itself