event sounds don’t play right

check this out..

http://support.microsoft.com/?scid=262256

Delete the null value in the registry. To do so:
Start Registry Editor (Regedt32.exe).
Click HKEY_CURRENT_USER.
Check for a value in the right pane that looks like this:
:REG_SZ:

If this value is present, click the value, and then press DELETE.
Quit Registry Editor.
You do not need to restart the computer to make the change take effect.