Car won't start

[HB.]

Today was raining pretty moderate when I left out. I drove about 3-4 miles to my bank to make a deposit. On my way to the bank I noticed that the car was acting a little funny, from time to time the hazard lights would flash once then go away. The door lock light would light up every couple of minutes. I really didn't think too much of it at the time, and kinda laughed in my head "my car is possessed". It took me less then 5 minutes to go inside the bank and make the deposit. When I came back to the car I noticed that it wouldn't start. The dash lights came on, the radio worked just fine, my headlights worked just fine, but the engine didn't turn over. At this point, I'm thinking damn it could be the starter, which at this point I noticed that the door lock button was dimly lit, so I tried to press it, nothing happened. I then tried the unlock button from the key, nothing happened. Now for some strange reason when I open one of the doors the rear trunk lid opens, and you can hear this slight buzzing sound coming from the rear of the car.

Has anyone dealt with this before, what could be wrong, and how much does this problem cost to fix?