{
The input strings for date and time depends on the format you are using.
}


procedure TForm1.Button1Click(Sender: TObject);
var
  SystemTime: TSystemTime;
  NewTime, NewDate: string;
begin
  NewTime := '12:00:00';
  NewDate := '01.01.2006'; 
  DateTimeToSystemTime(StrToDate(NewDate) + StrToTime(NewTime), SystemTime);
  SetLocalTime(SystemTime);
  // Tell windows, that the Time changed!
  PostMessage(HWND_BROADCAST, WM_TIMECHANGE, 0, 0); // *
end;
