The best IT hidden insult I heard was when someone called up with an IT issue, but actually there was no IT issues, it was just them, not knowing how to use the computer/software, etc. The IT bods would call the problem "BCAK", eg: Between Chair and Keyboard.The one I like (and used a heck of a lot when I was an IT Technician) if a person was seriously incompetent with a computer, I used an insult adapted from Dickens "He is in possession of equipment to which he can establish no legitimate pretensions". If the person being insulted is sufficiently stupid, they don't even realise I'm being rude.