'97 Altima Starts Erratically

I have a 1997 Altima that has been driving nuts. The lights got left on a couple of weeks ago and killed the battery. Ever since that happened the power door locks lock as soon as you turn the ignition on. The car was eqipped with checkmat auto security when it was purchased used. No documentation was supplied with the car. Now when it is damp outside it will crank but not start and sometimes it won't even crank. Not sure where to look but I dont want to spend a grand at the dealer on a car that is probably only worth 2.