Expanding a column

I'm having problems when I try to change the size of a column in one of my tables.  Basically, I want to hide a column (by initially setting the size to 0) and then expand it to show a table within this column.  The problem that I'm experiencing is that when the column expands to the correct size, the size of the preceeding columns in the table are then reduced and the format of the table is all messed up.  I'm using JavaScript to set the size of the DIV to 450.  Below is the JS & html that I'm using for my page.

<script language="JavaScript">
function ResizeColumn() {
      var objRS = document.getElementById("EmpInfo").style;
      objRS.display="block";
}
</scipt>

<table border="0" cellspacing="0" cellpadding="0">
      <tr>
            <td width="150"><p style="margin-left: 15">Employee Name</td>
            <td width="150">Title</td>
            <td width="0">
                  <div id="EmpInfo" style="display: none">
                        <table border="0" width="450" cellspacing="0" cellpadding="0">
                          <tr>
                            <td width="33%">InfoA</td>
                            <td width="33%">InfoB</td>
                            <td width="34%">InfoC</td>
                          </tr>
                        </table>
                  </div>
            </td>
            <td width="20" align="right">Yrs</td>
            <td width="10">x</td>
      </tr>
</table>

Please note that when the column is expanded, the table should exceed the size of the screen.  I noticed that the horizontal scrollbars do not appear at the bottom of the window when the DIV is displayed.