I used to work at an airport and they had a internal tracking system for passengers with special requests (mostly for unaccompanied kids).

Anyway it’s programmed in assembly and only works on one particular type computer. Even if it runs on a different era appropriate processor apparently this app won’t work. So there was a buttload of old motherboards in a store room somewhere so that we could just swap the board out if the computer ever died. It’s critical infrastructure that there is no backup for.

So basically I’m pretty sure the way the world ends is because somebody threw away an important floppy disk, and now a nuclear reactor is going into meltdown.