There is no error 
it just doesnt get registered i tried to look a bit online and im made some changes:

SqlConnection conn = new SqlConnection();
     SqlDataAdapter da = new SqlDataAdapter();
            SqlConnection sqlcon = new SqlConnection(@"Data Source=TZAHI-PC\SQLEXPRESS;Initial Catalog=RegisterDb;Integrated Security=True");
            DataBinder ds = new DataBinder();
            sqlcon.Open();

            SqlCommand sqlcmd = new SqlCommand("INSERT INTO dbo.Table2 (username, pass, repass, email, reemail , name , age) VALUES ('" + usernametb.Text + "," + passtb.Text + "," + rpasstb.Text + "," + emailtb.Text + "," + remailtb.Text + "," + nametb.Text + "," + agetb.Text + "')");
            sqlcmd.Parameters.AddWithValue("username", usernametb.Text);
            sqlcmd.Parameters.AddWithValue("password", passtb.Text);
            sqlcmd.Parameters.AddWithValue("repassword", rpasstb.Text);
            sqlcmd.Parameters.AddWithValue("email", emailtb.Text);
            sqlcmd.Parameters.AddWithValue("reemail", remailtb.Text);
            sqlcmd.Parameters.AddWithValue("name", nametb.Text);
            sqlcmd.Parameters.AddWithValue("age", agetb.Text);
            sqlcmd.ExecuteNonQuery();