How to get the running applications?

How to get the Running application(with window, not the process).
I tried to get the child windows of desktop, but it not working(or i dont know how to do it?)
will any one of u please help me out?
One more question.
i got teh HWND of ExploreWClass, then i tried to get the CWnd pointer of it, by calling FromHandle.
Then i called GetIcon , but it returns NULL(but it gets the CWnd Ponter). Please help me out, i want to get the icon of the running appications!