Оформил: DeeCo
Автор: http://www.swissdelphicenter.ch

function LastInput: DWord;
 var
   LInput: TLastInputInfo;
 begin
   LInput.cbSize := SizeOf(TLastInputInfo);
   GetLastInputInfo(LInput);
   Result := GetTickCount - LInput.dwTime;
 end;


 //Example: 
procedure TForm1.Timer1Timer(Sender: TObject);
 begin
   Label1.Caption := Format('System Idle since %d ms', [LastInput]);
 end;


 // The GetLastInputInfo function retrieves the time 
// of the last input event. 
// Minimum operating systems: Windows 2000