When I turn my computer speakers really loud, I can hear background noise from the circuitry.

What's weird, though, is that it makes a characteristic sound when I maximize, minimize or restore windows. "Minimize" causes a rising sound, whereas "Maximize" sounds like an impact, followed by a dropping sound. "Restore" has its own weaker version of each of those sounds... it's almost a purring sound.

This strikes me as weird, especially because I'm using the "Windows Default" soundscheme and all of these sounds are set to "(None)".