HOUSTON - Lawyers for Enron Corp. founder Kenneth Lay, who died of a heart attack last month, asked a federal judge to throw out his conviction for orchestrating the fraud that destroyed the world's largest energy trader. "Despite what may have been proven at trial, the trial is deemed not to have taken place," Sam Buffone, an appellate lawyer with the Washington firm of Ropes & Gray, wrote in a motion filed in federal court Wednesday. The request to erase Lay's conviction comes under federal law that says a defendant's criminal indictment and conviction can be thrown out if the person dies before exhausting appeals. Lay died July 5, roughly six weeks after he was convicted of spearheading the fraud that destroyed Enron. More than 5,000 jobs and $1 billion in employee pensions vanished overnight when Enron plunged into bankruptcy in December 2001.