Well you can delete all your incomplete files that are 0%. Click on top of Progress bar so all files are arranged in %. Then select all those at 0% & press Stop button. Then go to your incomplete folder, view it in size mode & delete all those at 0 KB.

Also try deleting your LW Preferences folder whilst LW is closed. Instructions here: Fixes for Limewire

Also if you have your search results up, select the file & press stop. Then re-select from results to downld. This can often give the file new life.