WALL-E

In 2805, Earth is abandoned and covered in heaps of garbage left over from decades of mass consumerism facilitated by the megacorporation Buy 'n' Large (BnL). Seven hundred years earlier, BnL evacuated Earth's population in fully automated starliners, leaving behind WALL-E trash compactor robots to clean the planet for humanity's eventual return. The plan failed, however, and all WALL-E units are now inactive except one, which has developed sentience after so many years of life experience. He manages to remain in operation by repairing himself using parts from other, inactive units.