If you were downloading 58GB it sure wasn't Gnutella, so why use an inferior Gnutella client instead of a proper BitTorrent program. Download Vuze (Azureus) or uTorrent and never do such stupid thing as using Limewire to download a 58GB sized torrent again ever.

That's how you prevent it.

You can try file recovery software to maybe retrieve the files, but there are no guaranties.