audioalert

When I first start up my computer the desktop icons load and look normal for about 2-3 seconds then they all turn white and it takes a few more seconds for them to return to normal. Then the computer makes a baDUMP ! sound. It other wise runs fine but this is driving me nuts.

On random occasions I get an audio sound, like an alert, like a doorbell (ding-dong, high pitch to low pitch). It is a full sound, with slight echo and reverb. I don't know what's causing it. I have gone through all sounds in the Sounds window in the Control Panel. It is none of those. I have...