0%? But you were just at 80%!!!!

For one, this program likes to disconnect whenever it feels like it, or freezes up my computer, which means I have to restart and reconnect. But when I do, the files which are partially downloaded in the Incomplete folder begin downloading from scratch. How can make the files in my download list recognize the files in the folder and simply finish downloading from that point. I would mind all the disconnects if they would truly resume, b/c the downloads are SUPERFAST, but I still usually can't make it all the way through one in one sitting. So what can I do?