Web Forms :: Login Page - Connection Was Not Closed / Current State Is Open

In my asp.net +vb+access web i have made a login page and the code is as under

Dim connectString As String = "Provider=Microsoft.Jet.OLEDB.4.0;" & _
"Data Source=C:webauth.mdb"
Dim con As OleDbConnection = New OleDbConnection(connectString)
con.Open()
Dim cmd As New OleDbCommand("select * from Users where userid =@userid and Password=@password", con)
cmd.Parameters.AddWithValue("@userid", txtUserName.Text)

[Code] ....

I am getting error The connection was not closed. The connection's current state is open.