I found this piece of code on page 661 from ASP 3.0 book writen by David Buser, which can solve your problem. You can try it.
<!--#include file="Clssfd.asp"-->
<%
Dim rsUsers
Set rsUsers = Server.CreateObject("ADODB.Recordset"

rsUsers.Open "Person", objConn, adOpenForwardOnly, adLockOptimistic, adCmdTable
If Session("PersonID"

<> "" Then ' currently logged-on user
rsUsers.Filter = "PersonID = '" & Session("PersonID"

& "'"
Else ' New session
rsUsers.Filter = "EMailAddress = '" & Request.Form("email"

& "'" & _
"AND Password = '" & Request.Form("password"

& "'"
If rsUsers.EOF Then ' User not found
rsUsers.AddNew ' ...so add a new record
' Else
' Email address and password matched with DB records -
' In this case we'll allow this to update user's personal details
End If
End If
' write personal details to record
rsUsers("EMailAddress"

= Request.Form("email"

rsUsers("Password"

= Request.Form("password"

rsUsers("FamilyName"

= Request.Form("FamilyName"

rsUsers("GivenName"

= Request.Form("GivenName"

rsUsers("StreetAddress1"

= Request.Form("Address1"

rsUsers("StreetAddress2"

= Request.Form("Address2"

rsUsers("City"

= Request.Form("City"

rsUsers("State"

= Request.Form("State"

rsUsers("PostalCode"

= Request.Form("PostalCode"

rsUsers("Country"

= Request.Form("Country"

rsUsers("Active"

= True
rsUsers("LastLogin"

= Now
rsUsers.Update ' update the database
Dim strName, strValue ' create session variables
For each strField in rsUsers.Fields
strName = strField.Name
strValue = strField.value
Session(strName) = strValue
Next
Session("blnValidUser"

= True ' declare that current user is validated
Response.Redirect "MenuForRegisteredUsers.asp"
%>