Do you mean that you're not seeing any search results, or that files won't download??
If you're not seeing any search results...
Is LW connected properly (all green/blue connection bars)? If LW is connected properly, try the fixes below.

1. In LW go tools > options > searching > basic & check whether the 'show license warning' box is ticked. If it does, untick it > Apply > ok...see if that makes any difference.

2. Problems with the search

3. 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 change all of your settings within options, you'll have to go back through afterwards & reset things to the way you like them.

If LW's not connected, try the tips below & post back with your details if need be.
If LW Will Not Connect