Strange system sounds glitch

Archived from groups: microsoft.public.windowsxp.help_and_support (More info?)

This problem started last week, after (strangely) spending a few hours on 3D
games (the last one played was Halo)

When Windows XP does one of the following:

-shutdown(log out)
-start up(log in)
-attempts to make the Question, Asterisk, Warning, or the Default sound
through popup boxes (for instance, the message boxes in the Office
applications) that are not the standard message boxes (i.e. the ones in
Explorer)

neither of these sounds play when they're supposed to. Other sounds, such as:

-minimize, maximize, restore up/down
-menu commmand/popup
-open/close program

these sounds continue to play whenever its respective event occurs.

In Windows XP's Sounds and Audio devices applet, every sound plays without
problems, so this isn't an issue about corrupt sound files (besides, they're
the default XP sounds).

I have tried reinstalling SP2 and the SB Live drivers, but nothing helped.
(System restore was disabled on this system.)

Anyone know which registry key or setting needs to be restored?