My Packard-Bell laptop is emitting a loud, annoying beep when I connect or disconnect it to/from an AC power source. Whether I have headphones plugged in or not does not change anything; the sound goes out of the speakers and wakes everyone up. Do you know of any ways to eliminate this sound? I searched around the Internet and found a solution involving setting a specific volume bar to 0 in the playback settings, but I did not find it on my laptop. I am using Windows 7.