I have both events for those keys (Qt 4.7.2 + windows 7). Here is my code:

Qt Code: 
  1. #include <QApplication>
  2. #include <QtGui>
  3.  
  4. class MyWindow: public QMainWindow
  5. {
  6. protected:
  7. 	virtual void keyPressEvent(QKeyEvent * event);
  8. 	virtual void keyReleaseEvent(QKeyEvent * event);
  9. };
  10.  
  11. void MyWindow::keyPressEvent(QKeyEvent *)
  12. {
  13. 	qDebug() << "key pressed";
  14. }
  15.  
  16. void MyWindow::keyReleaseEvent(QKeyEvent *)
  17. {
  18. 	qDebug() << "key released";
  19. }
  20.  
  21. int main(int argc, char * argv[])
  22. {
  23. 	QApplication a(argc, argv);
  24. 	MyWindow w;
  25. 	w.show();
  26. 	return a.exec();
  27. }
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make sure you have your widget focused.