Those 1 copy for yourself is called OEM.
Ahem version don't even bother. There's no such thing as
registration.
Install your modem drivers... otherwise, it has been installed by
XP and your connection is being managed by XP...
I have no idea who still mIRC today. If you are using Windows
Firewall, check that it's not blocking.
Other firewalls, make sure it's being allowed.