So, I'm moving away to grad school and I'm not taking my PC with me (I have a laptop). My parents are still struggling with their ancient desktop at home, and my father's day present to my dad is going to be my computer, all wiped clean and idiot-proofed.

My question to Reddit is what would you do, to ensure simple, reliable usage by my parents and 13 y/o brother (who just discovered you can see naked people online but doesn't understand that certain website will give you viruses) that they can't screw up like they screwed up their current PC?

Beyond the obvious: separate user accounts for them, with limited access blocking installation without the admin password, automatic backups, ONE internet browser labelled "Internet" on the desktop, etc.

TIA!