Stocks Fall Sharply, Fannie Mae Weighs  NEW YORK (Reuters) - Stocks were knocked lower on Wednesday  after a U.S. government review questioned home finance company  Fannie Mae's &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=FNM.N target=/stocks/quickinfo/fullquote"&gt;FNM.N&lt;/A&gt; accounting methods, while  investment bank  Morgan Stanley &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=MWD.N target=/stocks/quickinfo/fullquote"&gt;MWD.N&lt;/A&gt; reported a drop in quarterly profit.