[NumLock]

без использования VCL:

Код:

uses Windows;

procedure Sleep(dwMilliseconds: DWORD);
var
  SaveTickCount: Cardinal;
  Msg: TMsg;
begin
  SaveTickCount:=GetTickCount;
  repeat
    if PeekMessage(Msg, 0, 0, 0, PM_REMOVE) then
    begin
      TranslateMessage(Msg);
      DispatchMessage(Msg);
    end;
  until GetTickCount-SaveTickCount>=dwMilliseconds;
end;