I sadly fear that it is simply unreasonable to expect that any form of education is possible for many of these people. Indeed, that they ever had intelligence enough to breath is surprising, let alone having the intelligence to learn that "if you don't know the sender, don't open it!".
Such stupidity is widespread - how else do you explain the continued existence of windoze (no apologies to the fucktards who think it is an insult to their intelligence to call windoze anything but their preferred name - IDIOT! If you run windoze then it is clear - YOU HAVE NO INTELLIGENCE!), or either of mickey$loths top virus importing programs - outhouse and IE. If intelligence ruled the average life, none of these would be around to torment the rest of us.
Another area of dumbness - my neighbours have a direct link into my servers, giving them free internet. They use my email server as well.. Their wonderful, intelligent, helpful adult son, who is really good with computers, knows that ALL smtp servers have "smtp.domain" as their url, just like all pop3 servers have "pop3.domain" and so on. So intelligent that it never occured to him that some of us just use "domain", and if his parents email system was working fine like that, then probably he shouldn't be changing it, then complaining about the system no longer working.. The same intelligent one also was responsible for a shitload of virii and other crapware ending up on his parent's machine.
His parents are now happy users of Ubuntu, their system has not had a problem since the day it was installed.
I think that maybe the best idea would be, rather than just formatting their drives, switching them to something that looks like windoze but actually has something decent under the hood - something with some semblance of security.. Linux, OSX, BSD, some other *nix.
Educating them won't work, because if they use IE or outhouse then they're beyond help. But making it so they can't get infected, well, that's another matter.
Hmm.. Another possibility just sprang to mind.. Plant subliminal messages that tell them to take their computer to their nearest LUG (is the Apple equiv a "MUG"? :) ) and donate them, take it to their nearest charity.. Something like that might be good..
Oh, my neighbour's son is really pissed off coz there's no way in hell he is getting the password to that machine.
(Sorry - tired and "mildly annoyed" at having spent much of my friday night cleaning up yet another retard's fucked over crapware and malware infested windoze - surely we should be allowed to shove the mains lead up their arse and give them a shockingly harsh education in why "don't use that trash!" is NOT a request!)