Hide windows

Is there a software to hide all windows even when the system is busy?

 

If you mean what I think you mean, there is a built in Windows function to do that. Hold down the Windows (Start) key on your keyboard and press the M - let both go. How quickly the windows disappear depends on how busy the system is and how quickly it processes your request. Also, a slow or non-responding window may not minimise, so if you are trying to get back to the desktop, it doesn't always work. If the problem is a non-responding window, use the Task Manager to kill it and then the system should pick up in response time.

 

Another method is to press the windows key and the "D" key simultaneously.
This will minimze all your windows and show only your desktop