Handle under mouse pointer.

Getting the handle of an enabled window is easy just do..


(May have to strip it a bit)

Var
 Mpos: DWord;
 X,Y: Word;
 P: Tpoint;
 Wnd: Hwnd;
Begin
 Mpos:=getmessagepos();
 Y:=hiword(Mpos);
 X:=loword(Mpos);
 P.x:=X;
 P.Y:=Y;
 Wnd:=WindowFromPoint(P);
//Wnd = window's handle do was you please.

 End;

There is a small and smart tool, called Showin that can get the hwnd of a control, show/hide or enable/disable it, etc.
It can be downloaded here: www.foundstone.com/resources/forensics.htm

If you keep to doing this in Delphi, some useful Winapi functions:

Functions connected to mouse cursor
GetCursorPos(var Pt:TPoint);
SetCursorPos(x, y:integer);

Simulating mouse click at the position of the mouse, etc.
mouse_event(MOUSEEVENTF_LEFTDOWN, 0, 0, 0, 0);
mouse_event(MOUSEEVENTF_LEFTUP, 0, 0, 0, 0);

Getting window handle at a point:
WindowFromPoint(coordinates: TPoint);
ChildWindowFromPoint(parent_hwnd: THandle, relative_coordinates: TPoint);

Getting window/widget position to calculate relative coordinates:
GetWindowRect(hwnd:THandle, var rect:TRect);

Enable/disable window:
EnableWindow(hwnd: THandle, enable: boolean);

You'll find more information about these functions in MSDN.

But it still doesnt work as WinDowse... It gets the handle of the window but it does not show handle of component on that window...

Try to get the handle by a small freeware program called Showin
http://baixaki.ig.com.br/site/detail2516.htm

If it can't get the control's handle with Showin, I think you can't get it at all.
By the way, certain controls don't have hwnd (e.g. TSpeedButton in Delphi).

The code i gave you does get the handle of some components like buttons, radio buttons, forms.
You need different code for menus...even WinDowse cant get menus.