Soundblaster Live startup noise

Greetings,

I have a Soundblaster Live! in my HP Pavilion. For the past month or
so, I have had an incredibly loud sound during startup. It's a single
loud blast, that's so loud I have to turn off the subwoofer at startup
for fear of damaging the speakers.

The sound occurs after the "Windows XP Home" banner comes up, but
before the "welcome" message. Once Windows loads, the sound is
perfect.

I have updated to the latest driver, to no avail. Any suggestions for
troubleshooting?

Thanks in advance.