Hey, I have a 2003 Chevrolet Silverado 2500 and about a month ago someone left the lights on and killed the battery and its been sluggish ever since it was jumped off. Today I went to start it and it didn't have enough power to crank. Then finally it just stopped turning over. Turn the key and nothing. No sound. No click. All the lights and radio still come on though. What's going on?