Car Won't Start, No Power at All What Could Be the Issue?

96-Toyota Celica. Car was dead. Tried to jump it but it didn't start. Went to replace battery notice that the black cord was not grounded reconnected the cord. Lights came on and the car fired right up. Stayed on for a few minutes and died again with no power. Put the battery on the charger, nothing. Took the battery off the charger heard a click lights came back on the car started up again but died a few minutes later. No power since. Replaced the battery after all this and still no power at all (lights, sounds, or any movement) what could it be?

Suggestion:

NO, very easy, you've either got a bad ground, or just plain and simple loose connectors, check all of your possitive and negative connections, make sure they have no corrosion on them, and just make sure they are tight.