While I was out the alarm went off and my wife switched the alarm off. Now the car is completely dead and I can open the door with the key manually. But no led nothing comes on car won't come up the key won't work or anything. The alarm lights have been on for a while and just went off.

Any idea?

 

Seems odd that the battery would just suddently die but I suppose it's possible something shorted. I'd try a few things 1) try resetting the alarm by locking/unlocking the drivers door with the key 5X in a row. 2) if that doesn't work, measure the battery voltage. Should be 12.5V or so, under 12.2 won't start the car.

What year is your car?