Ex-Enron CEO Seeks Separate Trial  HOUSTON (Reuters) - Lawyers for former Enron Corp.  &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=ENRNQ.PK target=/stocks/quickinfo/fullquote"&gt;ENRNQ.PK&lt;/A&gt; chief executive Jeffrey Skilling on Friday asked a  federal court to separate his trial from his former boss Ken  Lay's on charges linked to the downfall of the energy company.