The answer to your question is A. the computer was defective. I really hope this helps!
B. have a main idea and supporting details
Since it's a personal narrative, you don't need a broad topic, in fact, smaller, emotional stories can help set the tone. They don't aim to make the world a better place so that isn't necessary either. It's not a research paper, so facts and statistics aren't necessary. What is necessary is to have a main idea and supporting details so your narrative will be well put together.
Headphones should be constructed so that when you play music the volume has to stay at a safe level meaning you can't control it so people don't blow their ear drums. Some people may like their music loud and others not so much so it wouldn't be fair if they couldn't control how high or low it goes.