When I set up a computer for my little brother, who is mentally handicapped and has a long history of bricking Windows installs, I installed Debian linux on it and set him up with a user account with minimal rights.
4 years later, it's still running. It needs my attention for a few minutes every few weeks to authorize updates. My brother cannot install, download or otherwise mess with anything important. He can't even change the settings for the wireless network, only turn it off and on.