Mac Fanboys, and PC Fanboys, and Fanboys in general are hated on because they're close-minded and they don't see the other side of things. That's what makes them so in your face about one thing being clearly superior to the other. Don't say Windows fanboys exist, because they do. There are lots of them, and they include those people that say Mac is total stuff or anything like that.
As for knowing stuff about computers, I deal with kids like this nearly every day in the Tech Office. We have two kids on the team right now who know jack stuff. They can barely follow simple commands properly. Unfortunately, we have to let them into the program and attempt to make them smarter because...well...it's a school, and for every new kid that joins the tech team the guy who manages us (not directly oddly enough) gets another $600 of budget money. The problem with the kids is, they want to fix everyone's computer because they play lots of computer games, or console games even. Basically, "Hurr, I play lots of video games, therefore I know lots of things about computers".
In the case of this kid being an idiot in front of the class in solving problems, just show them who's boss. Let's say a video isn't loading. "YO GUIS ITS CUZ ITS PC MANG" now you simply respond with "That's not the issue, you clearly don't know what you're talking about." Then you go on to quickly solve the issue and watch as everyone stares dreamily at your amazin' computer skills. Eventually he'll stop talking at all.
