Not really a question. If he went back to 6.16, it would probably not connect. It is almost guaranteed that the change in mIRC was a coincidence... unless he didn't get mIRC from an official source and it had a virus, of course. Even then, I doubt it was anything he did that caused it.
G-lines are not usually done because of a single person. If it's just one person, it's usually a k-line. A g-line is usually done when many people on a single host are causing a problem.
