const
 ExtendedKeys: set of Byte = [ // incomplete list
 VK_INSERT, VK_DELETE, VK_HOME, VK_END, VK_PRIOR, VK_NEXT,
  VK_LEFT, VK_UP, VK_RIGHT, VK_DOWN, VK_NUMLOCK
  ];
procedure SimulateKeyDown(Key: byte);
var
 flags: DWORD;
begin
 if Key in ExtendedKeys then
  flags := KEYEVENTF_EXTENDEDKEY
 else
  flags := 0;
 keybd_event(Key, MapVirtualKey(Key, 0), flags, 0);
end;
procedure SimulateKeyUp(Key: byte);
var
 flags: DWORD;
begin
 if Key in ExtendedKeys then
  flags := KEYEVENTF_EXTENDEDKEY
 else
  flags := 0;
 keybd_event(Key, MapVirtualKey(Key, 0), KEYEVENTF_KEYUP or flags, 0);
end;
procedure SimulateKeystroke(Key: byte);
var
 flags: DWORD;
 scancode: BYTE;
begin
 if Key in ExtendedKeys then
  flags := KEYEVENTF_EXTENDEDKEY
 else
  flags := 0;
 scancode := MapVirtualKey(Key, 0);
 keybd_event(Key,
  scancode,
  flags,
  0);
 keybd_event(Key,
  scancode,
  KEYEVENTF_KEYUP or flags,
  0);
end;