string sqlInsert = "insert into assessment (id) values (@id)";

        using (OleDbConnection conn = new OleDbConnection(dsn))
        {

            OleDbCommand cmd = new OleDbCommand(sqlInsert, conn);

            cmd.Parameters.Add("@id", OleDbType.VarChar, 50).Value = iDTextBox.Text.Trim().Length != null ? storedID.Trim() : "";

            conn.Open();
            cmd.ExecuteNonQuery();
            conn.Close();
        }

<add name="conn" connectionString="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|CADSCUPP.mdb" providerName="System.Data.OleDb"/>

private string dsn = System.Configuration.ConfigurationManager.ConnectionStrings["conn"].ConnectionString;

string sqlInsert = "insert into assessment (id) values (?)";

        using (OleDbConnection conn = new OleDbConnection(dsn))
        {

            OleDbCommand cmd = new OleDbCommand(sqlInsert, conn);

            cmd.Parameters.Add("?", OleDbType.VarChar, 50).Value = iDTextBox.Text.Trim().Length == 0 ? storedID.Trim() : "";

            conn.Open();
            cmd.ExecuteNonQuery();
            conn.Close();
        }

connetionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=yourdatabasename.mdb;"