Use QMessageBox.

messagebox_sample.cpp

#include <QtGui>

class MainWindow : public QDialog
{
    Q_OBJECT
public:
    MainWindow()
    {
        QPushButton *b;
        setLayout(new QGridLayout);
        layout()->addWidget(b = new QPushButton("&show"));
        connect(b, SIGNAL(clicked()), SLOT(showDialog()));
    }
public slots:
    void showDialog()
    {
        QString html = "<B>Score</B> : 100<BR>"
                       "<B>Score</B> : 200";
        QMessageBox *box = new QMessageBox(QMessageBox::NoIcon
                                           , "title"
                                           , html
                                           , QMessageBox::Ok | QMessageBox::Reset
                                           , this);
        box->setDefaultButton(QMessageBox::Ok);
        switch (box->exec())
        {
        case QMessageBox::Ok:
            qDebug() << "Ok"; break;
        case QMessageBox::Reset:
            qDebug() << "Reset"; break;
        default:
            qDebug() << "Unknown";
        }
    }
};

int main(int argc, char **argv)
{
    QApplication app(argc, argv);
    MainWindow w;
    w.show();
    return app.exec();
}

#include "messagebox_sample.moc"