asp.net - Row,column line of table not visible in IE

Question

  <table cellpadding="4" cellspacing="1" align="center" rules="all" class="ContentTable">
                <tr>
                    <td>
                        Active Students
                    </td>
                    <td>
                        <asp:TextBox ID="txtActiveStudents" runat="server" CssClass="TextBox" ReadOnly="true"></asp:TextBox>

                    </td>
                </tr>
                <tr>
                    <td>
                        Student/Teacher Ratio (Agreed Upon)
                    </td>
                    <td>
                        <asp:TextBox ID="txtRatio" runat="server" CssClass="TextBox" ReadOnly="true"></asp:TextBox>
                    </td>
                </tr>

            </table>

here is css

 .ContentTable
 {
border: solid 1px #EBEBEB;
border-collapse: collapse;
width: 98%;
vertical-align: middle;

  }

My problem is the table style not applied.

I want the table to be formated as rows and columns(borders).