I've just spent about an hour on the phone to my father, trying to lead him through what are painfully basic things for me, but which he manages to bugger up so easily!
For the last few years, I've got him a couple of Mini Macs on the basis that OSX is relatively difficult to break, and difficult to infect with malware etc, unlike the Windows 98 box he had prior to this.
Nevertheless, whenever he manages to do something strange, it can be a bugger to resolve it remotely, since as anyone who has done remote PC debugging knows, it's amazing how often strange things can happen in response to having done "nothing".
I've just managed to clear the print queue, but I still can't quite work out how he seems to have got whatever OSX uses to view PDFs into a state where it'll only print the odd pages of a document.