How to install and run old Qt4?

[Maluko_Da_Tola]

Hi everyone,

I created an application a good while ago in Qt4. Recentrly I installed Qt5 and it won't run, displaying an error: error: QDialog: No such file or directory #include <QDialog>

I did some google search and added 'QT += widgets' to the .pro file. Well this error was gone but 281 new errors featuring incompatilities with QLabels, etc appeared.

I then decided to jump out of Qt 5 and go back to Qt4. This is where trouble starts: I installed the Qt4 libraries from http://qt-project.org/downloads but I cannot find a way of running actual Qt4 or, alternatively, running Qt5 using the Qt4 libraries.

Any suggestions on how to get Qt4 to run on windows 7?

Thank you.
Maluko