There are more & more fake files on the network...these will sit connecting for ages & then get stuck needing sources forever. Maybe that's what you're seeing? Check out the threads below for info & tips to help
Fake files showing up in search results

How to find music (tips for movies as well)

If absolutely everything you try to download shows 'need more sources' (do a test...look for an old song & try to download a file with 10 sources or less, or a file with a modem source) then 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.

If you want to go back to basic LW, just download the latest free version from the site below. Installing a new version of LW will automatically remove your current LW version. So, unless you have your Pro installer saved, you'd lose whatever Pro version you're using now
Lime Wire » Download LimeWire