How can I disable the beep when I plug in/unplug my laptop's AC adapter?

I think the option that will matter to you is the Power Control Beep. It's a BIOS setting, so you'll have to restart your computer to change it.

1. Either restart your computer, or shut it down and then power it back on.

2. When the boot process starts, open the BIOS settings menu. How you do this depends on your computer. Usually, it involves pressing F10, F1 or F12 on the first screen that comes up, before the "Starting Windows" animation appears.

3. In the BIOS settings, use the arrow keys — directions should be provided on-screen — to navigate to the Config menu, then the Alarm sub-menu.

4. Set Power Control Beep to "disabled." If you want to get rid of other beeping at the same time, you can set Low Battery Alarm and Password Beep to "disabled" as well.

5. Save and exit the BIOS settings application. Again, directions for this should be on screen. In my case, it was as easy as pressing F10 followed by Enter.

6. Depending on your computer, you may be asked which device you want to boot from. Select whatever you usually use (typically the HDD, or hard drive).

7. Tell your family members that they will no longer be woken up by your computer.