So we're going to reformat my GF's machine this evening. When we shut it down, after the computer turns off, there is some "blipping" coming from the speakers, and the CPU fan is "bouncing". My thought is the PSU is going out and this bouncing and blipping is some cap either on the motherboard or the PSU discharging. Oh yeah, when you turn the PSU off, the blipping and etc stops. When you turn it back on, it starts again. If you fire up the machine with the on button, the system starts up normally.