The key in the ignition message is due to the key sensing flap being stuck, needs a wash out with switch cleaner such as Aero klene 50. As long as the system thinks the key is in when it isn't you will have a problem.
How did you check the battery is charged? If it was looking at the indicator, that shows just one cell and will still be green when the battery is half charged. A new battery should always be charged before fitting as the alternator will take for ever to fully charge a half charged battery leading to premature failure.