urjosito ayudame con un combo???

[yoyi2002]

<form name="form1" method="post" action="actualizar_proveedor.asp">

<table width="771" border="0" cellpadding="0" cellspacing="0">
<tr>
<td width="172" height="360"></td>
<td width="427" valign="top">
<table width="100%" border="0" cellpadding="0" cellspacing="0">
<tr>
<td width="1" height="10" ></td>
<td width="141" ></td>
<td width="31" ></td>
<td width="253" ></td>
<td width="1" ></td>
</tr>
<tr>
<td height="22" ></td>
<td colspan="4" valign="top" bgcolor="#000099" >
<div align="center"> <font color="#FFFFFF" size="4"><b><font size="4">Actualizar
Proveedor</font></b></font></div>
</td>
</tr>
<tr>
<td height="19" ></td>
<td ></td>
<td ></td>
<td ></td>
<td ></td>
</tr>
<tr>
<td height="28" ></td>
<td valign="top" ><b><font face="Verdana, Arial, Helvetica, sans-serif" size="2">Rut:</font></b></td>
<td colspan="2" valign="top" >
<%set conexion = conecta()
set rs=Server.CreateObject("ADODB.Recordset" )
sql= "select * from proveedor"
rs.open sql, conexion %>


<select name="combo_rut" style="width:115" onchange="document.form1.submit()" >
<option>Seleccione</option>
<%do until rs.eof %>
<option value="<%=rs("rut_proveedor")%&g t;"<%if request("combo_rut")=rs("rut_provee dor") then%>SELECTED<%end if%>>

<%=rs("rut_proveedor")%></option>
<%rs.MoveNext
loop%>
</select>
<%rs.Close %>
<% if request("combo_rut")<>"" then
set conexion = conecta()
set rs=Server.CreateObject("ADODB.Recordset" )
sql="select * from proveedor where rut_proveedor='"& request("combo_rut") &"';"
rs.open sql, conexion
if not rs.eof then%>

</td>
<td ></td>
</tr>
<tr>
<td height="28" ></td>
<td valign="top" ><b><font face="Verdana, Arial, Helvetica, sans-serif" size="2">Servicio:</font></b></td>
<td valign="top" >