A group of hackers launched a series of attacks Thursday after Dept. of Justice officials shut down Megaupload, a file-sharing site suspected of providing illegal access to copyrighted works.  The hackers shut down the websites of the Justice Department, the Recording Industry of America, Universal Music Group and the Motion Picture Association.  Universal has been embroiled in a legal battle with Megaupload for months, stepping up the intensity after a video surfaced online last month that featured Kanye West, Alicia Keys, Swizz Beatz and other big name artists apparently endorsing the piracy hub.