Login problem

    Hi Everyone,
Good evening. Can you help me point out what seems to be the problem with my applciation? I know my problem will be a piece of cake to you guys.
 
I have a login page where the user will input his username and password:
 
here is the code:
  

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
 
        If Not IsPostBack Then
            Try
                status = Request.QueryString("status").ToString()
                If status = "NOTADMIN" Then
                    lblWarning.Text = "Sorry you are not allowed to access the site. Please contact Site Admin."
                End If
            Catch ex As Exception
                Dim a As String = ""
            End Try
        End If
    End Sub
 
    Protected Sub ImageButton1_Click(ByVal sender As Object, ByVal e As System.Web.UI.ImageClickEventArgs) Handles ImageButton1.Click
 

        If TbUsername.Text <> "" OrElse TbPassword.Text <> "" Then
            Session.Timeout = 480
            Dim accessData As New DataAccess()
            Dim User As String = TbUsername.Text
            Dim Username As String() = User.Replace("\", "|").Split("|"c)
            Session("Username") = Nothing
            Dim Authentication As Boolean = IsUserAuthenticated("LDAP://" & Username(0).ToString(), Username(0).ToString(), Username(1).ToString(), TbPassword.Text.Trim())
            If Authentication = True Then
                StaticObject.UserName = ""
                StaticObject.Password = ""
                StaticObject.Domain = ""
 
                StaticObject.Domain = Username(1).ToString()
                Session("UserName") = Username(1).ToString()
 
                StaticObject.Domain = Username(0).ToString()
                accessData.AddUser(Username(1).ToString())
                Dim Authorization As String = accessData.CheckUserAccess(Username(1).ToString())
                Dim MyAuthorization As String() = Authorization.Split("|"c)
                StaticObject.UserLevel = MyAuthorization(0).ToString()
                StaticObject.IsAdmin = MyAuthorization(1).ToString()
                If MyAuthorization(0).ToString() <> "9" Then
                    Session("displayName") = StaticObject.DisplayName
                    Response.Redirect("Home.aspx")
 
                Else
                    lblWarning.Text = "Sorry you are not allowed to access this Site, please contact the Site Administrator"
 
                End If
            Else
                lblWarning.Text = "User Name or Password incorrect! Note: 3 consecutives incorrect login your account will be locked!"
            End If
        End If
 
    End Sub
    Public Function IsUserAuthenticated(ByVal strAdPath As String, ByVal strDomain As String, ByVal strUserName As String, ByVal strPassword As String) As Boolean
        Dim directoryEntry As New DirectoryEntry(strAdPath, strUserName, strPassword)
 
        Dim directorySearcher As New DirectorySearcher(directoryEntry)
        Dim Authentication As [Boolean]
 
        Try
 
            Dim searchResult As SearchResult = directorySearcher.FindOne()
            Authentication = True
            ' authenticated 
            'string a = directoryEntry.Properties["displayName"].Value.ToString();
            directorySearcher.Filter = "(&(objectClass=person) (samaccountname=" & strUserName & "))"
            Dim result As SearchResult = directorySearcher.FindOne()
            Dim resultEntry As New DirectoryEntry()
            resultEntry = result.GetDirectoryEntry()
 
            'Properties.Item("displayName").Value.ToString())
            StaticObject.DisplayName = resultEntry.Properties("displayName").Value.ToString()
        Catch ex As Exception
            Authentication = False
            ' not authenticated 
            TbUsername.Text = ""
            TbPassword.Text = ""
        End Try
        Return Authentication
 
    End Function
 
   
 
End Class

so basically it is using windows login.
 
The poblem is that :
The page does not recognize that there is already a session. Therefore, still showin the login button when it should be logout because the user was able to login.
 
Here is the code:

 Private user As StaticObject = Nothing
    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        If Session("displayName") Is Nothing Then
            lblUserFullName.Text = "null"
        Else
            If Not Page.IsPostBack Then
                Try
                    lblUserFullName.Text = StaticObject.DisplayName
                Catch ex As Exception
                End Try
            End If
        End If
    End Sub
    Protected Sub loginstatus_LoggedOut(ByVal sender As Object, ByVal e As System.EventArgs) Handles loginstatus.LoggedOut
        Session.Abandon()
        Session.Clear()
    End Sub
    Protected Sub loginstatus_LoggingOut(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.LoginCancelEventArgs) Handles loginstatus.LoggingOut
    End Sub

thank you very much in advance and I made sure I did my best to fix this before seeking for help.