Page validation works once but not twice then text box lose value

Hi
I'm trying to validate an update form that has data from the db,
The problem is when I delete the text in the text box and click submit I get the message "title required" which is correct. But if I click submit again without filling in the text box I lose all the data in all the text boxes.

Can anyone help solve this problem for me.

*********** Code ****************
<script runat="server">
string strUserName, strPassword;
void Page_Load(Object Src, EventArgs E)
{
Session["strUserName"] = Request.Form["Username"];
Session["strPassword"] = Request.Form["Password"];
if (IsPostBack)
{
Page.Validate();
        if(Page.IsValid)
            {
            Response.Redirect("confirmation.aspx");
    }
}
}
</script>

<asp:textbox MaxLength="25"  id="Company" text='<%# CustDetails.FieldValue("Headline", Container) %>' TextMode="SingleLine" Columns="32" runat="server" />
        <asp:RequiredFieldValidator ControlToValidate="Company" Display="Dynamic" EnableClientScript="true" ErrorMessage="" ID="strValCompany" runat="server" Text="Title required" />
        <asp:RegularExpressionValidator ControlToValidate="Company" Display="Dynamic" EnableClientScript="true" ErrorMessage="" ID="strRegCompany" runat="server" Text="Max 20 characters" ValidationExpression="(.|\n){0,20}" />

Thanks
George