讓程式不能重覆開啟

//專案檔最前面加上，1.檢查Mutex，若XMonitor已存在，則離開。
if ProgramAlreadyExists() then exit;

function ProgramAlreadyExists():boolean;
var
  hRunningForm: Thandle;
begin
  //g_hMutex:=CreateMutex(nil, False, 'X-Console');
  g_hMutex:=CreateEvent(nil, False, TRUE, 'X-Monitor');
  if (g_hMutex=0) OR (GetLastError()=ERROR_ALREADY_EXISTS) then //已存在
  begin
    hRunningForm := FindWindow(_XMONITOR_CLASS_NAME,nil);
    if hRunningForm<>0 then
    begin
      SetForegroundWindow(hRunningForm);
//      PostMessage(hRunningForm,WM_SYSCOMMAND,SC_MAXIMIZE,0);
    end;

    Result:=true;
  end
  else
    Result:=false;
end;