Car wont spark up. Changed battery, fixed fuse recently. Now it overheated and wont start up?

My car wouldn't start for a long time & I finally took it to get fixed, turned out it was a simple fuse that needed to be replaced. Ran like a dream for a few weeks then I started noticing that the lights wouldnt come on sometimes, and all the electricity stopped working. I bought a brand new battery and it fixed that for a few days. Then, my car started over heating, I shut it off & something under the hood exploded with a loud bang & greenish yellow stuff all over and smoked for a while. It wouldnt start. I let it sit for a few hours, started right back up. Then I noticed my lights were on for a few hours, killed the battery. Let it sit, started back up. A few hours later, I got on the freeway, and noticed my car was rapidly heating up. It stopped accellerating and I pulled over. No loud bang this time but smoke bellowed out for a while. I popped the hood & let it cool off. It wouldn't start. Wouldn't crank. The lights dimmed until eventually they were so dim I couldn't even tell I had them on. I got a jump & the car still wouldn't start, but the lights got brighter. Anothet jump and still no start, it would crank but no spark. As of now the car is still doing that. No spark, and only cranks when I have the battery hooked up to a charger. And my lights keep working, then not working. Like they are killing the battery even when they aren't on? I don't know anything about cars, So I've come here. I need to figure out what is wrong.