Trying to fix my daughters 2007 Civic. It had been sitting for several months due to her having a knee injury. Tried to start it and nothing. I charger the battery for a couple hours and got it going. but it sat for another three weeks or so and when you put the key in there are no lights or anything dashboard is totally blank. Battery is at 12.8 volts sitting there and I cleaned the connections and still nothing. I now see that there is an Immobilizer? Would that totally shut the car down no power to anything?
Thanks in advance

 

Nothing with key on? No lights? Power problem not immobilizer.