1999 Honda Accord just bought and lights on

I 've never owned a honda before I have some lights on in the dash flashing doors ,battery, and brake light? I checked the alternator at autozone they said it read out fine the batttery was alittle corroded so, we cleaned that with the cleaner from autozone the battery read out still good too when hooked up it was noted though that the battery is alot bigger than necassary for the car. I think I got hosed on this car I called the number on the key chain to see if it had repairs before and I found out the previous owner the guy who sold it to me was the general manager of the dealership I thought he was a regular joe private party. I spent alot for the car and now I have this to deal with? I hope you may know what this is. Thankyou