[ecfisa]

Hola.

Intenta de este modo:

Código Delphi [-]
...
var
  Ip: TInput;
begin
  ZeroMemory(@Ip, Sizeof(TInput));
  Ip.Itype          := INPUT_KEYBOARD;
  Ip.ki.wVk         := VK_LWIN;
  Ip.ki.wScan       := 0;
  // Key Win down
  Ip.ki.dwFlags     := KEYEVENTF_EXTENDEDKEY;
  SendInput(1, Ip, SizeOf(TInput));
  // Key Win up
  ip.ki.dwFlags     := KEYEVENTF_KEYUP;
  SendInput(1, Ip, SizeOf(TInput));
end;

Saludos