@GarySibley:
Thanks for the feedback, and I'm glad that you found it. Although I'm not surprised that an msiInstaller error might have caused a "Critical Stop" but I wouldn't have thought that it would continue issuing the error ever few seconds.
@JudsonWelcher:
I suggest that you also check your Event Viewer for msiinstaller errors. I've seen other posts where a "critical stop" sound seemed to be related to such errors (but as I said above, not to continuous repetitions of the error).
There's no easy way I know of to track down this sort of thing. Before you start the "Clean Boot" method or begin using Process Monitor, open the Sounds control panel applet and scroll through to check that Windows XP Critical Stop.wav has not been assigned to some event in addition to (or in place of) an actual Windows Critical Stop.
For help with Process Monitor, go here -->http://forum.sysinternals.com/process-monitor_forum19.html
To check your Java installation, go to http://java.com/en/download/testjava.jsp