2008 Subaru outback : Last Sunday, my wife and I both used our key fobs at the same time, and while she was able to start the car with her key, we couldn't auto-lock it. Now, I just went to drive the car for the first time since then, and my fob doesn't work, and the car won't start. totally dead.
If the vehicle is totally dead the problem could be the battery, that is where I would start. See if it can be jumped and if it starts see if anything was left on in the vehicle to drain the battery if nothing is noticeable have the battery tested.