Battery dies within 3hrs

[NCG]

I posted this to another forum earlier,sorry..new to this.

Here goes,got up at 8am,drove to fast food joint,came back,car was fine.Round noon,went to remote start it and nothing.Changed batteries in key fob,still nothing.Walked down to the car,realized nothing was working.No courtesy lights,instrument lights,even had to use the real key to unlock it.Fast forward till 8pm,had car jumped,ran like it always did.Drove to gas station,started right up,pulled into the driveway,even started it again just to be safe.Walked back out about 3hrs later,and everything was dead again.The only thing that was lit up was PRNDS on the dash.Thats it.Just those buttons.

[Viking]

Well, the very first thing I would do would be to charge up the battery till it showed full, if it ever does - then load test it.  If the load test fails, you need a battery before you can go any further with this.  Also, if the battery will not charge up to full (12.6 volts) then you may need a new battery.  Either way, you need a good battery in the car to attempt diagnosis of anything else.