Good day everyone, A friend of mine brought a laptop (Compaq Evo n610c) to me for check-up, and this is what I found out. 1. The laptop cannot start without AC power even when the battery is inserted. 2. The battery is not charging at all. 3. When you unplug the AC power cord leaving the battery in the laptop, there is some noise coming from somewhere near the battery. The noise is audible when the laptop is shut down. I need help to locate the exact problem and ways of solving it. Thank you.