Title: Minimize All Windows on Desktop
Question: You have to minimize all windows, but don't want to send simulated keystrokes or messages to all applications? You can do it with Shell commands.
Answer:
To minimize all the windows on the Desktop manually, you need to right-click the taskbar and select "Minimize All Windows" (Win 98) ; another solution requires a click to the "Show Desktop" icon in the "Quick Launch" area of the taskbar (Windows 2000 or Windows XP).
Finally you can press the Windows logo key and the M key simultaneously. Unfortunately, you can't programmatically send this key combination to the Windows shell or any other application.
You can use the Shell API Application object, take a look on the code:
uses ShlObj;
procedure Shell_MinimizeAll;
var
Shell : OleVariant;
begin
Shell := CreateOleObject('Shell.Application');
Shell.MinimizeAll;
end;