Why do I have No power at all in car but the battery is charged?

What is your question?

2012 Acadia, base model, 125000miles. I did a long repair job on the car (timing chains) and had the battery unhooked for about 2 weeks. Went to start up, key in, turned, no lights on dash, no overhead lights, nothing. Battery is charged, 12.81 reading. I used a meter to read the positive lug under the hood, nothing, no reading. Checked the positive post on the alt, nothing. Visually checked fuses they are good. Cleaned up battery posts and lugs under hood, resecured, still nothing! Key gets stuck, each time, figured out how to release, tried other set of keys, same thing. Any advice? Thanks!