After a couple of months being parked, I tried to start my 2006 Maserati Quattroporte Executive GT and discovered the battery was completely dead (this is a pretty new battery, probably haven't started the car with it more than 10-15 times since new). Due to a tendency the car had for the battery to go down over time if not driven often, I have been keeping the car's battery hooked up to a "floating" charger that featured a shut-off when the battery reached full charge and that was supposed to maintain a full charge when and if the battery got low. Sometime while the car was parked over the past months, the cord going to the charger got unplugged at the wall and the dead battery resulted. I plugged the charger back in and left it overnight. The next day, with a full charge on the battery, I started the car. To my dismay, I got all kinds of lights and warnings on the instrument cluster that I've never seen before. I turned the car off, disconnected the negative battery cable from the car to the battery and waited 20 minutes to reconnect it. Once I reconnected the battery, I started the car again. Most of the lights and warnings were gone. However, the display screen for the sound system/navigation, etc. did not come on, the climate control display came on showing only one random number in the left side of the small screen, the sport button didn't work, the manual/automatic shift button didn't work, neither of the rotary function buttons (for setting the clock, etc.) work, the glove box door will not latch when shut if the car is not running, etc. There may be other issues that I haven't found yet, but these are the ones that were readily apparent. The car does drive and the transmission shifts (manually only), however. Has anyone had an experience like this, and what can be done to fix it or at least diagnose the problem? I am 500 miles from the nearest dealership, so its not really convenient to take it in. I'd really appreciate any help or suggestions.