Once, some critical .dll files had been deleted from the Windows XP Operating System on one of the shared computers in my house, rendering the system un-usable. Nobody had made any backups, and the XP Installation DVD was nowhere to be found.
I didn't want to leave my family with an un-usable machine, so I bit the bullet and installed Debian Linux with Firefox(which I believe was branded IceWeasel at the time), OpenOffice, and some other essentials. After hearing feedback from my parents, I switched to Ubuntu (with the same apps) for the sake of user-friendliness.