Help please. Electrical problems c+c 2006

2 weeks ago the hazard lights started flashing whilst the car was being driven, they wouldn't turn off unless the battery was disconnected. We put a new battery in the intelligent key fob and the problem went away for 2 weeks. Now the hazards are flashing, the drivers airbag light is on, the engine kept running for a couple of mins after turning the ignition off and there is a constant whine from under the bonnet whether the engine is running or not. Any ideas?