Hi I have a 96 intrepid sat for a while and was dead when I went to start it.so I give it a boost and it starts but the radio, pwr window's, pwr locks, and all the lights where going crazy. then after a minute it dies. so I unhook and clean the battery and cables give it another boost this time it starts without acting all crazy but as soon as I unhook the booster cables it die's .. not sure do you think its the battery or the alternator...any help would be great thank's.