Asklemmy

Not a movie, but a TV show. Revolution.

A sci-fi post-apocalypse show where the premise is that all of a sudden all technology (specifically anything that uses electricity) just stops working and nobody knows why. The show takes place 15 years into the apocalypse. The US has Balkanized into various regional states (although you don't learn this until later). Some regions have devolved into chaos while others have basically reverted to a steam-punk type of society. Since all modern ships use electricity, they've begun to revive large ships from the age of sail. The remnants of the US military at Guantanamo Bay eventually return to the mainland and try to reestablish a much more explicitly authoritarian control over the US. You eventually learn that what caused the global blackout was the creation of a self-replication nanotech which rapidly spread across the planet and shut off all electricity.

Great premise, but it got too much into the soap-opera CW-style of writing and didn't last more than 2 seasons.