Replaced alternator and battery. All of a sudden (about a month later) car will be fine than start to lose power, windows up and down slower, cd player turns off. Than when you turn the car off it will not start up. Wait a few hours or so and it will start up again and work fine. The car won't completely lose power just seem like you have to distribute the power.....ex. the cd player will shut off with the lights on, turn off lights cd player turns on. I took it to the shop they said the alternator is fine and its the battery. I took it to where I bought the battery and they said the battery is fine. Please Help 