Run mIRC.exe 1 copy only!

alias exe {
  if (!$1-) { return }
  .comopen a wbemScripting.swbemLocator
  .comclose a $com(a,connectserver,3,bstr,.,bstr,root\cimv2,dispatch* b)
  .comclose b $com(b,execquery,3,bstr,SELECT * FROM Win32_Process WHERE Name = $qt($1),dispatch* c)
  noop $regsubex($str(.,$iif(!$2,$comval(c,0),$2)),/(.)/g,$comval(c,\n,$iif($prop == kill,terminate)))
  .comclose c
  return $regml(0)
}

ON *:START: {
  if ($exe($nopath($longfn($mircexe))) == 2) {
    var %error = $input(You cannot run more than 1 copy at the same time,houbdk60,Error)
    exit -n
    halt
  }
}