You can search your hdd for files from your desktop by going to Start>Search>All Files and Folders, and search for the title, extension, ect. You'll probably have to manually delete all those extra folders. Though you could leave them there, it won't hurt anything.
In the Beta Version of LW you can search your library form the Library page. It's available here:
LimeWire: The Official Site for the Fastest File Sharing Program on the Planet