a windows application with full control over all installed apps Qt/c++
I want to develop a windows application that displays all apps installed on the system. From my app, I will be able to launch any installed app or lock it. Please which Qt class or properties is meant to do this.
Please which Qt class or properties is meant to do this.
simply none, since this is way out of scope of the Qt framework.
You can use Qt for the GUI and utility classes but you will need to use the WinAPI for most of the logic.
The launching part is very clear but
what does it mean "to lock it" ?
What you want is called a kiosk mode and to do it you need to configure your system properly. Most of it is OS level configuration and this is not something any app can do, Qt or not. You can use Qt to make a fullscreen app but that is not nearly enough.
The topic is vast. Here is some Windows 10 specific info to start you in the right direction, but there's certainly more: Set up a kiosk on Windows 10.